picasso, matisse and the parisian avant-garde. >> woodruff: and margaret warner explores why yemen's president ali abdullah saleh remains in power amid growing violence and calls to step down. >> ifill: that's all ahead on tonight's newshour. major funding for the pbs newshour has been provided by: >> okay, listen. somebody has got to get serious. >> i think... >> we need renewable energy. >> ...renewable energy is vital to our planet. >> you hear about alternatives, right? wind, solar, algae. >> i think it's got to work on a big scale. and i think it's got to be affordable. >> so, where are they? >> it has to work in the real world. at chevron, we're investing millions in solar and biofuel technology to make it work. >> we've got to get on this now. >> right now. ♪ ♪ ♪ ♪ ♪ moving our economy for 160 years. bnsf, the engine that connects us. pacific life-- the power to help you succeed. and the william and flora hewlett foundation, working to solve social and environmental problems at home and around the world. and with the ongoing support of these institutions and foundations. and... this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. >> ifill: a new report out today shows the state of the housing market has grown even more bleak. the new figures from standard and poor's found home prices have continued to drop for more than two consecutive quarters. homes lost value in all but one of the 20 major markets tracked by the case-shiller index during the first three months of this year. compared to a year ago, prices are down 7% or more in several cities. and in atlanta, cleveland, detroit, and las vegas, prices are headed toward levels last seen more than a decade ago. but what is driving this stubborn downward pressure? for that, we turn to rick sharga, senior vice president of realty trac, a web site that publishes data on real estate and foreclosure trends; and mark zandi, chief economist at moody's analytics. rich sharga, are these numbers proof of a double-dip recession, that term we've all feared? >> certainly not a double-dip recession. i mean in the overall economy. but you can make an argument about the double dip in the housing market. it depends upon your definition of a double dip. is a 5% drop compared to a 20% drop a couple years ago a double dip or is it just a continuation of a downward trend that the market is trying to correct? not good news however you want to define. >> ifill: in your opinion what are the driving factors, say the two or three big driving factors here. >> well, obviously 9% unemployment rate is a problem. tough job market makes it hard for people to go out and buy homes. i think the foreclosure crisis is a very serious weight on the housing market. we have millions of loans in the foreclosure process that will go through and are going through to... and the homes get sold at a big discount, at a price cut. that's driving prices down as well. and confidence. if you look at the consumer confidence numbers, people are still very nervous and scared. of course nothing takes a higher level of confidence than signing on the dotted line to buy a home. if people aren't feeling really good about their financial situation, that's going to be hard on the housing market. >> ifill: what would you identify as the major driving factors in this in. >> i think mark is dead on. i think he's probably hit the major identifying factors. it really comes down on the one end to a supply-and-demand imbalance. the inventory far, far outstrips the buying activity currently going on. i think one of the exacerbating factors is that it continues to be stubbornly difficult for the average home buyer to qualify for a loan. we have historically low interest rates and relatively few people who qualify to get these loans. and i don't think the foreclosure problem can be overestimated. a number of the cities that you're focusing on with the largest drops-- las vegas, cleveland and detroit among them-- have been among the poster children for markets that just have extraordinarily high numbers of foreclosure properties at remarkably low prices that pull the entire market down with them. >> ifill: mark zandi, you talked about confidence. i wonder if that's not affected when we talk about the foreclosure numbers. people look at how badly this all went after the bubble. they think to themselves, you know, i don't really need to own a home anymore. how much of that is playing a part in this? >> certainly it is playing a role. i mean i think nobody wants to catch the proverbial falling nights. when prices are weak and falling you don't want to take the plunge, buy a home and of course lose value 6, 12 months down the road. it's a bit of a chicken-and-egg kind of problem. people are very nervous if they buy today the value of their home will be less in the future. it's probably a deeper, longer- term issue as well. many people are viewing housing very differently than they did in the past. like, for example, i know my parents thought of their home as a way to fund their retirement. i'm just thinking about my home as hopefully holding its value. but my son, my kids, are probably thinking, you know, is this a good buy at all? if the prices in their lifetime have fallen so sharply. i think attitudes with respect to owning a home certainly as an investment are changing. that's affecting demand as well. >> ifill: rick sharga, is there another vicious cycle here which is if you worry that you cannot get a home, if you worry that you can't get a loan, if you're worried that you cannot keep a job that all of that drives... lessened demand as well for all these homes clogging up the market? >> you know, we recently surveyed a potential home buyers across the country. the number that jumped off the page at me is that 40% of the renters we surveyed said they decided never to buy a house. that number just hit me right in the face because we're coming only a few years off historically high levels of home ownership. i think almost 59%. the next generation of homeowners, to mark's point, 40% of them have already opted not to participate in the housing market. so it's a frightening number. the only reassurance i can give is that we do know that consumer sentiment has a way of swinging wildly back and forth. so if we do begin to see job creation, if we do begin to see a return of consumer confidence, if the housing market begins to stabilize, hopefully that consumer sentiment can swing back toward where we have a more active buying market. >> ifill: mark zandi, we talked about the 20 cities involved in this particular study. is this a regional problem we're talking about now or are we talking about a true national overhang, a hangover from the boom years here? >> well, it's a national problem. every corner of the country has been impacted. prices are down almost everywhere. there are some bright spots. you know, texas, for example, parts of the farm belt. but outside of that we've seen foreclosures increase, house prices decline. yeah, i think you could consider this a national house price decline. in fact, it's unprecedented. you'd have to go back to the great depression in the '30s to find a time when so many markets have suffered such large price declines. so it is a national phenomenon. >> ifill: you mentioned the depression. that was the biggest economic shock that any of us have had experienced or perhaps or parents experienced. how much of this slowdown in the housing market is going to end up driving the entire economy's recovery off track? >> well, that's a good question. you know, i think the economy is growing. it can continue to grow without housing. but it certainly cannot flourish. i don't think this economy really can engage. it can't create the kind of jobs we need to bring down unemployment in a substantive way unless housing is headed north. and in every economic recovery that we've experienced since the great depression, housing has led the way. so we need housing. we need it to come back. i think there are some good things that are coming together. but the longer we have to wait, the more nervous i get about the recovery and the economic expansion. >> ifill: rick sharga, do you see any good things coming together and should they be given by the federal government or the private sector or even state government? >> neither of the government initiatives that we saw last year either suspended foreclosure activity or the home buyer tax credit really had the intended effect. after the second tax credit sales volume went so far down that it pulled home prices down perhaps even further than they would have gone otherwise. i think unfortunately the remedy to the housing market right now is probably time. we need time to create more jobs. we need time for consumer confidence to come back. we need time for lenders to actually feel comfortable enough to start making loans on properties that have values that are stabilizing. and then the market will start to recover on its own. but i don't see government intervention as being a part of the solution right now. >> ifill: is there anyway to know whether this is an anomaly for now or if it's a long-term problem. >> the continuing falling of home prices? >> ifill: yeah. >> i think there's probably a little bit more to go. i would be interested to hear what mark said but i think we're very close to the bottom. unfortunately we'll probably bump along that bottom for a couple of years while we go through this inventory of distressed properties. >> ifill: do you agree with that, mr. zandi? >> i think the key statistic for house prices are the homes for sale that are distressed. as that share rises prices will fall. the math of it is that prices will fall. i do expect the sales that are distressed will continue to rise through the year. prices will probably bottom out at the end of this year. by this time next year i think we'll start to see some true price stability, in price gains. i think we have to get through this#çò last mountain of foreclosed property and on the other side of it i think we'll be in measureably better shape. >> ifill: mark zandi and rick sharga, thank you both very much. >> thank you. >> thank you. >> woodruff: still to come on the newshour: a debt ceiling showdown; a possible cell phone/cancer link; early connoisseurs of the french avant garde; and an embattled president clings to power in yemen. but first, the other news of the day. here's kwame holman. >> holman: the fighting in afghanistan claimed more lives today-- an unidentified nato soldier was killed in the east. and the u.s. military announced three americans died in a bombing on saturday. the new combat casualties brought to 55 nato deaths in the month of may. the total included at let 31 americans, fewer than the 43 in april. meanwhile, afghan president hamid karzai ordered nato today to stop air strikes on afghan homes. it was his strongest statement yet on civilian casualties, and it followed a saturday strike that killed 14 women and children. >> the afghan people can no longer tolerate these attacks on their homes. one day the afghan government will be forced if you do not come to an understanding with us based on a negotiated solution to this, that is the prevention of bombardment of afghan homes, the afghan government will be forced to take a ewen eye lateral action in this regard. >> holman: karzai did not say what he meant by "unilateral action," but nato answered that its air strikes still are essential in fighting the taliban. syrian president bashar al-assad issued a general amnesty for all political prisoners today. state-run television reported the amnesty covers all crimes committed before today, possibly affecting thousands of people. at the same time, syrian troops attacked the town of rastan with tanks and heavy machine guns. activists said at least one person was killed. and the u.s. state department condemned the tortured killing of a 13-year-old syrian boy, identified as hamza ali al-khateeb. "the new york times" reported the boy was arrested at a protest, and his mutilated body was returned later to his family. north and south sudan have agreed to set up a demilitarized border zone patrolled by both sides. the african union announced the arrangement today, after escalating clashes in recent days. i spoke this afternoon with rebecca hamilton of the pulitzer center, reporting from juba in south sudan. rebecca, what is the assessment there of how this talk of an agreement that would stop the dispute in the central region might affect the kind of problems of refugees being displaced in the central region? >> everybody is happy to see that the two sides are talking. but this idea that this agreement is going to fix the immediate humanitarian crisis just doesn't seem realistic. for people here it seems very far removed. >> reporter: we've heard a couple of different reports, one that the ethiopian army would comprise the peace-keeping force, if you will, and the other that there would be some sort of joint north-south operation. soldiers from east side. what's the story there? >> yes, there are two separate proposals under discussion. the ethiopians, it seems, have offered to... peacekeepers if a peace keeping dough ploiment goes into a town. separate of that is the discussion of how the new demilitarized zone along the border areas that may or may not include abiyah, it's unclear yet. they would be compriseded of representatives of both north and south. >> reporter: rebecca, the problem of the rain and lack of food and lack of fuel, what can be done quickly to address the kinds of concerns you've been talking about? >> certainly there needs to be a clear passage from the north back into the south. whatever it takes to get that to happen needs to happen really as quickly as possible because time is short for these people that are sheltering under the rain right now and in particular for the children. and then the issue of abiyah itself, it's very hard to see a resolution while the sudanese saying that it is keeping its forces there, that it is northern land and that it won't withdraw. so any agreement needs to deal first with that question of whether the sudanese government is going to withdraw from abiyah at all. >> reporter: sudan is scheduled to gain its independence from the north in july. in libya in libya, moammar qaddafi vowed to remain in his country, defying rebel demands to leave. that word came from south african president jacob zuma, who returned home after meeting with qaddafi. a spokesman for the libyan government said the two did not discuss an exit strategy. ratko mladic was extradited from serbia today to face a u.n. war crimes tribunal in the netherlands. the former bosnian serb general is accused in the murders of 8,000 bosnian muslims and other atrocities. we have a report from paul davies of independent television news. >> reporter: the sudden presence of dozens of heavily armed special police officers outside his belgrade prison was the first sign that, after a 16-year wait, justice was finally moving fast for ratko mladic. somewhere in this convoy bound for the airport, and ultimately the international court at the hague, is the bosnian serb general whose attempt to avoid extradition on grounds that he wasn't well enough to travel had just been rejected. >> with the extradition of ratko mladic to the hague, the republic of serbia has fulfilled moral and international obligation, and with it can prove that we meet our commitments. >> reporter: these are the only moving pictures of mladic we've seen since his arrest last week. his family say he's suffered two strokes and won't survive a trial. this rally in banya luka today was the latest protest staged by those who still see mladic as a war hero, not the war criminal with the blood of thousands on his hands as he's perceived elsewhere. in this atmosphere, the government will be pleased to see the back of him. >> holman: hours after flying out of belgrade, mladic arrived in rotterdam. his plane touched down as evening fell, and a waiting convoy of police vehicles took him to the u.n. detention compound outside the hague. the u.s. supreme court has ruled that former attorney general john ashcroft cannot be sued over a post-9/11 arrest. the decision today was five to three in the case of abdullah al-kidd, an american muslim. al-kidd was arrested in 2003 and held for 16 days. he was repeatedly strip-searched and left naked in a jail cell, but he never was charged with a crime. the high court ruled ashcroft did not violate kidd's constitutional rights. president obama nominated john bryson to be secretary of commerce today. bryson is a former chairman and c.e.o. of edison international, an energy firm based in california. he also co-founded the natural resources defense council. the current commerce secretary, gary locke, has been tapped to become ambassador to china. wall street finished the month on a high note amid talk of a new financial bailout for greece. the dow jones industrial average gained 128 points to close at 12,569. the nasdaq rose 38 points to close at 2,835. those are some of the day's major stories. now, back to judy >> woodruff: house republicans have staged a largely symbolic vote this evening on a bill ostensibly aimed at raising the nation's debt limit by an additional $2.4 trillion. the measure has no spending cuts attached to it and is, therefore, all but certain to fail. earlier today at a white house news briefing, press secretary jay carney said that deficit reduction talks between the administration and congress are making progress, but ultimately, the ceiling will have to be raised. >> we also believe quite strongly that we have to raise the debt ceiling. there is no option to doing that. and that that will happen. because the economic impacts of not voting to raise the debt ceiling would be calamitous. >> woodruff: we now head to the other end of pennsylvania avenue where we are joined by leading members from each party to tell us what's behind tonight's vote. representative peter roskam of illinois is the chief deputy republican whip and sits on the house ways and means committee. and assistant democratic leader james clyburn of south carolina. he is a member of the bipartisan deficit group led by vice president biden. gentlemen, thank you both for being with us. >> thank you for having us. >> thank you. >> woodruff: congressman ros kum, do you first. almost all the congress watchers we've been talking to say this is a purely symbolic vote with no real substantive meaning to it. >> it's very substantive in that it's a request of the president of the united states. uts one that he has affirmed over and over and over again and that is to simply raise the debt ceiling without any reforms or no substantive spending cuts. in order to move the debate forward what we're going to see today is that the country overwhelming rejects that approach. i predict it won't pass but it won't just be republicans that are going to vote against this. it will be democrats that will vote against it as well. but it's on the floor because it's the request of the president of the united states. >> woodruff: it's symbolic because republicans don't typically salute and do exactly what the president is asking. >> right. we're a co-equal branch of government but in order to move the debate forward, there's got to be an end to this idea where the white house just continues to say, give us more authority to spend more money without setting up a substantive plan to cut the deficit and to bring things into balance. >> woodruff: the republican leaders, congressman roskam, apparently didn't want to rattle the financial markets. you're scheduling this vote late in the day. and i would reading today, we know that you were told or that wall street was somehow told, reassured that this was a symbolic vote. my question is, how was wall street reassured? there was a chamber of commerce official who says that wall street is in on the joke. >> i don't know either way whether any kind of phone calls were made, but i think most folks on wall street recognize the foolishness of moving forward and simply without any pre-condition whatsoever giving the white house more authority to spend more money. they probably are in on the joke. i think ultimately it's the american public that says, "this has to stop." >> woodruff: well, congressman clyburn, your party has said that this is a vote that's all for show. and yet it was a majority of democrats who just last month said they wanted a stand-alone vote on the debt limit. still your leadership is telling democrats tonight to vote no. which is it? >> well, i'm going to vote no. i'm going to vote no because it is a joke. the fact of the matter is that the letter that went out, i think that mischaracterized by a lot of people. that letter signed by more than 100 democrats askd our caucus to come out in support of a clean vote. it did not ask the republican leadership to put that on the floor. nor did the president ask them to put it on the floor. what we know is that this vote is not about things going forward. it's about the capacity to pay the debt currently owed. i think that if more people understood that that's what we're doing here, trying to prevent default on debt that we currently owe, this has absolutely nothing to do with our spending going forward. so i believe that that... if you were to characterize it correctly, the american people would have a different attitude about what we're doing. >> woodruff: but congressman clyburn, won't the result of this vote if the majority does vote no-- and i guess that's the expectation-- won't that show that you won't have a debt ceiling increase vote without spending cuts to match it? >> well, as you said earlier, judy, i am a member of the deficit reduction committee. that's chaired by vice president biden. we are making significant progress. the whole atmosphere in the room for every meeting is a very good one. and our staffs are meeting this week. we will begin meeting again next week when the senate returns. and i think we're making great progress. and we have been told that we're... we'll have until the end of july to get something done. so i think that we ought to let that process go forward. we ought not be taking these kinds of sham votes and misusing the process because that's how the public gets misinformed about what we're doing. when we do things that we know are not serious and we ought not to be playing game s with the american people this way. >> woodruff: however it's characterized, representative roskam, we heard the white house press secretary jay carney say again today that there's no alternative to raising the debt ceiling. that anything other than that would be calamitous. do you agree with him? >> i agree that the president of the united states, judy, needs to come forward with a plan, a plan to address the reality of where we are right now. so far president obama has given a speech while we say very simply, mr. president, please give us your plan that can be then scored by the congressional budget office and evaluated. i'm all for meetings in rooms with good atmospherics but when it comes down to it, we need the president to lead and to articulate a plan because absent a plan, there's really no appetite right now to deal with it. it's very important that the president lead with a plan ultimately to bring this country back into balance. >> woodruff: isn't that what these negotiations under vice president biden are all about? do i hear you saying that raising the debt ceiling may not have to happen? >> no, what i'm saying is any raise of the debt ceiling has to be pre-conditioned upon cuts that drive towards a real economic recovery and long-term growth and prosperity and job creation. the whole notion of just simply moving along and giving the white house a blank check is a complete non-starter. >> woodruff: picking up on that, congressman clyburn, we know that your colleague steny hoyer, the house democratic whip, has said that everything has to be on the table in these talks going on under vice president biden, including medicaid. is that something that you accept? >> let me remind listeners and watchers, judy, last november the democrats addressed medicare in the continuing resolution that we passed. and that continuing resolution had a $500 million cut in medicare. did not cut one dime out of medicare benefits. it cut $500 million out of the providers' side. so i think that we have demonstrated that we know how to address the medicare problems. we can do so without cutting one dime out of benefits. this thing of just cutting benefits, inflicting pain on seniors, is something democrats are not going to do. i'm not going to.... >> woodruff: so you disagree with your colleague, mr. hoyer, who says that additional cuts in medicare have to be on the table? >> well, i'm not disagreeing. i didn't hear what mr. hoyer had to say. i'm just saying that we have demonstrated that we know how to deal with medicare without affecting benefits of seniors at all because we demonstrated that last november. and, i might add, the republicans used that against us in their campaigns last november when they knew full well that they were not telling the elderly the truth about what we had done. >> woodruff: gentlemen, we are going to have to leave it there. we will certainly be coming back to this. we'll be watching this vote tonight very closely. congressman peter roskam, congressman clyburn, we thank you both. >> thank you so much. >> thank you. >> ifill: now, an international panel of scientists is raising questions about whether there's a link between cell phones and cancer. jeffrey brown has the story. >> brown: the news led to provocative headlines, all triggered by an announcement from a panel of the world health organization. a team of 31 scientists from 14 countries said radiation emitted by cell phones is "possibly carcinogenic," and may be associated with "some risk" for brain cancer. but the group also said that evidence of a direct link is still far from clear, and it called for more study. a cell phone industry group put out a statement that today's news "does not mean cell phones cause cancer." to walk through what is and isn't known, we're joined by dr. keith black, chair of neuro- surgery and neuroscience at cedars-sinai medical center in los angeles. dr. black, welcome to you. what does possibly carcinogen i can mean exactly? >> what it means is that the world health organization panel of scientists looked at the current available evidence that's been published as well as some unpublished data that should be coming out shortly from the multinational study and concluded that the evidence suggests that there is a possible link between cell phone use and brain cancer. this is looking at multiple studies. the best conclusion at this point would suggest that there is the possibility for a link. >> brown: now the issue is the radiation, right? explain what researchers are concerned about and what they're studying. >> essentially a cell phone is a microwave antenna which generates microwave radiation. we know that microwave radiation can penetrate into the brain when you hold the cell phone next to your ear. in fact, it's related to the square of the distance. so the closer, you get a much much greater amount of radiation going into the brain. that radiation and energy when it hits biological tissues, there is some concern that it may actually cause cells over a long term time period to transform from normal cells into cancer cells. >> brown: to be clear now, this is a shift for the who, but as i said in the introduction, at the same time researchers said that they have not found a direct link so far. tell us, what is it that we don't know and what makes this hard to make a direct link? >> what we don't know currently is whether cell phone use is safe. we don't know that it is unsafe. the problem that we have is that about half of the studies have shown that there is no correlation to brain cancer and cell phone use. half of the studies that have been done have shown a correlation. the problem that we have is that the studies that tend to show no correlation tend to be studies that look at people that have had very short time periods of cell phone use and very low amounts of minutes of using the cell phone. the studies that do show a correlation tend to be studies that have looked at people that have used cell phones for a period of ten years, for example, and are using cell phones, say, for 30 minutes a day. higher-term use. so the longer-term studies, the studies that have been somewhat better designed although still flawed have tended to show this correlation. the problem we have is that we know that most environmental agents that cause cancer don't cause cancer after a month or a year or two years of exposure. the best example i can give to illustrate this is that if one was to start smoking cigarettes when they were 12, we don't expect them to develop lung cancer when they're 22. we expect them to develop lung cancer when they're 42 or 52. three or four decades of exposure. we just don't have that long period of study with people that have used cell phones. >> brown: of course people wonder what they should do. this group did not propose guidelines or regulations. as to advice to consumers, i noted that one of the researchers said pending the availability of additional research, it is important to take pragmatic measures to reduce exposure such as hands- free devices or texting. fill in that picture for us. what advice would you give people given what we know and what we don't know. >> you know, the best thing is to be informed. i think the best thing for consumers and the best thing about the w.h.o.-statement is that at least consumers can be aware that there is a potential risk and, therefore, they could begin to sort of take measures to use the cell phone more safely. even if you read the insert in the cell phone, it will tell you to hold the cell phone an inch or so away from your ear so that the radiation doesn't go directly into the brain. best to use an ear piece. best to use it on speaker mode. best to use text. if you're driving, best to use hands-free. and not to put the cell phone, you know, right adjacent to your brain. the other thing to be aware of is that we haven't had any good studys in the pediatric population. a child's skull is much thinner. the amount of radiation that goes into the pediatric brain is much higher than in the adult. so we should be cautious with how we allow our children to use the cell phone. they're going to be the ones using it at a much younger age and using it over a much longer duration. >> brown: just briefly... i'm sorry. just briefly, i can't resist asking you, dr. black. what about you yourself. does this change how you use the cell phone? >> i use a cell phone. but i always use it either on speaker mode or use it with an ear piece or text. i don't put it next to my brain. you know, i think to also just to put this in context for your viewers, you know, the risk of developing brain cancer is about 6 per 100,000 in a population per year. so even if the risks were to double, you're looking at about 12 cases for 100,000 in the population. it doesn't mean that, you know, we're going to be walking down the street and people are going to be falling over dying of brain cancer. you know, the overall number of people that develop brain cancer, you know, is not like lung cancer or breast cancer. it's a little smaller. but what's important to recognize is that if you do develop brain cancer, it's one of the most devastating illnesses that you can have. so if you want to take precautions, at least you're aware that your cell phone is not necessarily a safe device and use the things we've outlined: ear piece, speaker moed can be a safer way of using it. >> brown: dr. keith black, thank you so much. thank you very much for joining us. >> thank you. >> woodruff: now, san francisco recreates a world-class art collection. newshour correspondent spencer michels reports. >> reporter: in turn-of-the- century paris, the american writer gertrude stein held court for avant-garde painters and writers at the homes she shared with her brothers and sister-in- law. she had been raised in oakland, then went to baltimore, but paris was where the art scene was. century-old photographs of their apartments show the walls nearly hidden by paintings of picasso and matisse and others the family had bought cheaply, a collection that was dispersed over the years. today, that amazing assemblage of groundbreaking art has been reassembled at the san francisco museum of modern art. the exhibition brings together over 150 pieces that were once owned by the steins from five different continents, from public collections, from private collections-- really, from all over the world. >> reporter: janet bishop, one of the show's curators, says this wasn't just any art collection. stein scoured art galleries and shows, buying paintings by unheralded artists like pierre bonnard, paul cezanne, juan gris, as well as picasso and matisse-- the cutting edge artists of the day whose work, not yet famous nor expensive, gave rise to fauvism, cubism and surrealism. >> the steins were really essential to the development of modern art in the early 20th century. their homes became the crossroads for dialogue, and anyone who was interested in seeing the most interesting new art being made in paris at the time really had to go to the stein residences. >> reporter: for years, bishop and others tracked down the collection and convinced current owners to part with their treasures for exhibition here, then in paris, and finally-- next february-- in new york, a very expensive journey. in san francisco, the paintings were examined minutely on arrival for pre-existing faults or flaws. in the museum's conservation room, some of the work received a little touching up, a little cleaning, the removal of old varnish, perhaps some reframing, everybody being very careful. the steins were not wealthy art patrons-- they had a modest inheritance from a father who operated cable cars in san francisco, and they spent most of it on paintings and sculpture destined to become extremely valuable. >> gertrude stein famously said "you can buy art, or you can buy clothes, but you couldn't do both". so the steins decided to focus on artists who were their peers, artists who had not yet made their reputations. >> reporter: henri matisse was a family favorite. in 1906, gertrude stein and her brother leo saw this matisse at a paris salon, unsold. >> leo and gertrude stein stepped forward at the very end of the exhibition and offered matisse a discounted price, and he accepted it. and as soon as that painting got to their home on the rue de fleuris, people needed to go see it. it had been the most notorious submission to that year's salon. notorious because even matisse's wife, who was the model, was embarrassed by the colors that didn't correspond to nature. >> it was one thing to do that with a landscape, but to take that palette and apply it to a portrait of a woman, to a woman's face, to paint a woman's face green, was utterly shocking and unprecedented. >> reporter: the painting-- "woman with a hat"-- is today regarded as a masterpiece, and graces the cover of the catalogue. in 1907, the steins bought a matisse called "blue nude"-- on a painting, bishop says, that had a profound influence on picasso. it shows matisse presenting a traditional subject of a bather in a very powerful, aggressive way. >> it was an immediate challenge to picasso, and he launched into a series of drawings and paintings that respond directly to the "blue nude." >> reporter: the stein pictures and sculpture at san francisco moma would be a worthy exhibit, even without the story of the steins. but obviously, the steins add a lot of interest. across the street, the contemporary jewish museum has mounted a companion show centered around the life of gertrude stein. as a character, stein was a fascinating study. and wanda corn, art professor emeritus at stanford and guest curator of this stein show, has delved into her life and her friends. >> many of her friendships, it need be said, were rather short- lived, because she would quickly move on to another interest, another artist, another project that she was taking on. >> reporter: one friend she did keep was her companion, alice b. toklas, a major feature of this exhibit. >> gertrude and alice fell in love, and eventually alice moved into the apartment of leo and gertrude. it was gertrude who continued to bring artists into them. >> reporter: but gertrude stein wanted to be more than a collector. >> she liked collecting, but after awhile, her public image as a patron and collector bothered her. she wanted to be known the same way picasso was known-- for her creative work, not just for her collecting of others. >> reporter: stein thought of herself primarily as a writer, whose work, corn contends, has come back into fashion. >> she was always just a little outside the mainstream until, really, feminism rediscovered her and began to look at her through a completely different lens. >> reporter: in addition to writing several books, including the best selling "autobiography of alice b. toklas," stein composed the libretto for a cutting-edge opera composed by virgil thompson, "four saints in three acts," with an all-black cast, produced in 1934. both museums are showing excerpts. as a writer and as a collector, gertrude was a very strong personality who encouraged her own celebrity, and loved being painted and sculpted. perhaps the most famous portrait is by picasso, which both museums are featuring, in different forms. >> gertrude tells this wonderful story of having sat in picasso's studio for some 80 or 90 sittings in a broken armchair. then, at one point, he got completely fed up. he went off to the pyrenees for the summer, and when he got back to his studio in paris, he repainted the head completely and made her very mask-like-- and that really was a fundamental step toward cubism. >> reporter: wanting to insure her own legacy, stein left the picasso portrait to the new york museum of modern art, the only painting she willed to a museum. both san francisco shows, anticipating summer crowds, remain up until september 6. >> ifill: finally tonight, a sometime u.s. ally falls deeper into chaos. margaret warner has the yemen story. >> warner: heavy fighting resumed today in yemen's capital, sana'a, after a cease- fire broke down between president ali abdullah saleh's government troops and tribal militia. it was the latest bloody twist in a four-month-long standoff between saleh and three different groups trying to bring him down. the militia fighters in sana'a are loyal to the large, powerful hashed tribe, led by a saleh rival, sheikh sadiq al-ahmar. >> ( translated ): we will not allow saleh to lead yemen to civil war. he attacked our houses and we are steadfast. >> warner: elsewhere yesterday, government gunmen in the city of taiz rained fire on another group of saleh opponents-- younger anti-government demonstrators. and in the south, yemen's air force pounded islamist militants who took control of the city of zinjibar last friday. amid all this, the crumbling regime of president saleh lurches onward, despite his repeated pledges to leave office. just five weeks ago, saleh said publicly he'd agreed to abdicate under a deal brokered by the saudi-led gulf cooperation council and backed by washington. but the next day, he expressed defiant reluctance. >> ( translated ): this is a coup. you call on me from the u.s. and europe to hand over power. whom should i hand it over to? those who are trying to make a coup? >> warner: saleh has ruled impoverished yemen for 33 years. he faced threats even before arab spring-style street protests erupted in late january. they included rebellions in the north and south, and an al qaeda terror franchise headquartered in the sparsely populated eastern part of the country. this potent al qaeda offshoot triggered ever-deeper u.s. involvement in yemen and support for saleh. but this spring, after government forces began killing protesters, the u.s. began working with the saudis to ease him out. last week, after missing two agreed-upon deadlines to sign the agreement, saleh balked a third time. >> ( translated ): we do not want any foreign intervention or solution from outside of yemen. it is a yemeni issue. we should go into a dialogue with all political sides. a solution will come from us and not from the outside. >> warner: a day later, speaking in paris, secretary of state hillary clinton made her toughest statement yet on saleh's status. >> we continue to support the departure of president saleh, who has consistently agreed that he would be stepping down from power, and then consistently reneged on those agreements, turning his back on the commitments that he made, and disregarding the legitimate aspirations of the yemeni people. >> warner: now, in a country awash in weapons, those aspirations are on hold. instead, fears abound that this nation of 22 million could disintegrate into chaos. what explains president saleh's survival? for that, we turn to barbara bodine, who served as u.s. ambassador to yemen from 1997 until 2001. and bernard haykel, a professor of near eastern studies at princeton university. professor haykel, after all these deals and these forces besieging him. he is still there. why? and how does he do it? >> i mean he has always ruled in this chaotic way, dividing up different forces in yemen, playing off outside powers against each other and also threatening yemen and promising that he's the only person who can keep it together and therefore getting money from either the saudis or the americans in order to stay in power. he's always ruled in this way. he wants to stay in power clearly and thinks that he can either outwitt or out, you know, live out the patience of most of his opponents. >> warner: do you see him that way, ambassador bodine? do you think he never did intend to live up to any of these deals? >> i'm beginning to think that he probably did not intend to live up to them. i think particularly when we got to the g.c.c. brokered agreement, that one had the largest backing including us and all of the g.c.c. members. it's the one that he most clearly said he would sign. he has outwitted all of his opponents over the last 30 years but i think now he is starting to make some serious tactical mistakes. unfortunately we're seeing the results of that. >> warner: briefly, what do you mean tactical mistakes? give me one. >> well, constantly agreeing and then reneging. particularly this g.c.c. one because he lost a lot of backing. the basic sense of most outside countries, outside powers was to have a negotiated settlement between the opposition and to have some kind of reasonable transition as opposed to mubarak or ben a.l.y just simply stepping down. >> warner: professor, back to you. let's talk about the outside parish. you had all the gulf neighbors including the saudis wanting him gone. why can't they pull it off? isn't he dependent on the saudis financially? >> he has received financial support from the saudis. they i think have now given up on him. the problem with the saudis in particular is that the candidate that they would like to replace him with is a relative of it who is really the continuation of the same system and would not be acceptable to most yemeni. >> warner: i see. and how about the opposition, professor, staying with you for another minute. just the opposition itself. i mean, you have all these different factions in the op igs. is there any cohesion or any ability to actually pull something off here? >> i mean the opposition is quite divided. the problem is also that the opposition is not representative of the populist movement that has overtaken this country. these large, young people, large numbers of young people who are so far peacefully demonstrating don't have a leadership and are not organized around the older opposition members. so you do have a country that is very, very fragmented. >> warner: ambassador bodine, he's also played as the professor mentioned earlier, the sort of "it's me or al qaeda" or "it's me or chaos" card. is that still working with him with either his own people or say with the u.s.? >> i don't think it's working any longer. it's been more "it's either me or chaos." as professor haykel pointed out, there isn't an obvious or agreed successor. but what we're seeing is that what we've got now is him and chaos. not him or chaos. so i think that card is no longer really a strong card. >> warner: professor, this sort of takeover of the city on the southern coast, the government seemed to hint that this was al qaeda and the arabian peninsula connected or something. yet there seems a lot of the skepticism about that. >> yeah, there is. you know, as ambassador bodine has just mentioned i think he's overplayed his hand. this may be just another attempt again to use the al qaeda card. it's not clear that in fact it is al qaeda that has taken over this city. if at all. >> warner: who else would it be? >> oh, it could be local tribesmen, southern... there's a southern secessionist movement. there's also a man who is the defender of the old leader who is one of the big leaders in that town and has his own men. >> warner: back to you, ambassador, how does this... how is this likely to play out? >> i don't think anyone has the real answer on that. it's going to have to be negotiated. if you run through the various options in that sense the statement that it is going to have to be a yemeni solution and somehow negotiated, i would think that if not the g.c.c., one of the g.c.c.- members probably not saudi will have to come in and broker some kind of a deal. or this is just going to continue to spin out of control. no one will win. absolutely no one. >> warner: professor, that scenario depends on saleh actually wanting to leave. do you see anything that would break either his will or his ability to hang on? >> i think that, you know, the big question is how much money does he have at his disposal? he is not able to wage a war against all yemenis if you can't buy off his own supporters. this has always been the rule of thumb in yemen that you need to spend money on the tribes in order to mobilize them to your side. i'm not sure how much money he has or how much money he's will to go actually spend to mobilize support against this formidable opposition that is now against him. >> warner: professor haykel and ambassador bodine, thank you both. >> thank you. >> thank you. we reported earlier that the u.s. supreme court ruled that former attorney general john ashcroft cannot be sued over a post 9/11 arrest. that decision was 8-0. again, the major developments of the day: a key survey showed home prices in major u.s. cities have hit the lowest levels in five years; and to kwame holman for what's on the newshour online. kwame. >> holman: the newshour's web site is back up and running following yesterday's hacking incidents. we apologize for any inconvenience. all that and more is on our web site, newshour.pbs.org. gwen. >> ifill: and that's the newshour for tonight. on wednesday, we'll look at computer sabotage as a fact of life in this wired world. i'm gwen ifill. >> woodruff: and i'm judy woodruff. we'll see you online and again here tomorrow evening. thank you and good night. major funding for the pbs newshour has been provided by: >> okay, listen. somebody has got to get serious. >> i think... >> we need renewable energy. >> 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