good evening to you tonight from afghanistan, where this is a big moment in the history of this conflict, the ten-year war, the longest in america's history. at the white house today, the president held a meeting to talk about the beginning of the exit. how many of the 100,000 troops currently stationed here should be brought home, and all of this amid the continuing clamor from congress to accelerate the withdrawals and do something about the $10 billion a month being spent on this war. but as you're about to hear, the two men at the top, secretary of defense robert gates and the general in charge, david petraeus, are making the case to be careful, keep the military pressure on. so who is right? and what is the answer to the questions americans are asking? are we winning this war? that is where we start. are we winning this war? >> we have had a great deal of success in achieving the mission our forces have been given. >> is that the functional equivalent of winning? >> we're making progress. >> they'll try to come back though, and that's why we say these gains, while significant, are fragile. >> fragile, in part, because petraeus and gates say if the military pressure is strong enough, there is a possibility of peace negotiation by this winter. if we don't let off the pressure now, there is a real possibility of a negotiated settlement by the end of this year? >> it's hard to handicap that, diane. >> if we can't talk about winning, if we don't talk about military victory, it is too much to ask of american men and women to put their lives on the line for the hope of a negotiated settlement with the people they're fighting? >> diane, we have not had a declared victory in a war, with the possible exception of the first gulf war, since world war ii. it is the phenomenon of modern conflict. are the american people safer at the end because of the sacrifice these soldiers have made? that's the real question. >> not yet, the kind of critical mass that sets off a chain reaction that we saw in iraq. but that's an important development. >> and there's no question the surge of american troops has achieved something formidable. look at the map. they actually reclaimed the critical south, including kandahar, the spiritual home of the taliban. but the fighting continues on the border. which raises the question, how many troops can the u.s. afford to start bringing home? the president has said a significant number should come home by july 11th. while just this weekend, the defense secretary countered with the word "modest." does president obama understand the impact of taking too many out? >> well, that's a discussion -- i mean, that's a judgment call that has to be made. in the context of a wide variety of issues that the president has to face. >> you said, mr. secretary, modest draw-down. the president has said substantial draw-down. modest, significant, substantial. >> the question depends on what time frame you're using. i mean, whatever -- compared to 100,000 troops or 150,000 coalition troops, any number that's not completely off the charts in july is going to seem like a modest number. what i have said is that it is important, as we did in iraq, to have a strategy behind the numbers, not to just pluck a single number out and say, okay, that's the number, as i've been talking about with the budget. that's math, not strategy. >> general petraeus, are you saying, give us more time, don't take, what's the number, five, ten, don't take more than that, give us more time this year? >> well, again, look, the decision ultimately is the president's. our job is to provide options and then to assess levels of risk. it is ultimately the president's decision. and of course the congress needs to -- we need to have congressional support. but they also need to understand consequences. >> congress keeps saying in essence, hey, we've had a $10 billion a month is unsustainable. >> the cost is already coming down. we will be spending $40 billion a year less on these wars in 2012 than we did in 2011. i think you also have to ask the question, what's the cost of failure? we've invested a huge amount of money here. we've invested 1,254 lives up to this point. so what's the cost of getting it wrong? congress -- congress is almost always impatient. i remember in the spring of 2007, people said this thing is lost -- >> you said they had short-term thinking? >> yeah, absolutely. i can say that since i'm leaving in a few weeks. >> and leaving this partnership, petraeus and gates, literal war buddies for so many years. gates is going to retire. petraeus go to the cia. but the problems will remain. for instance, what about the afghan national army? 86% of that army still cannot read. >> there's no question about the progress of the afghan national army. >> when we hear the mixed reports out on the field still, mixed reports? >> i think you probably hear the most mixed reports on the police frankly. >> then there's pakistan with that wild flurry of brand-new drone attacks. possibly targets retrieved from osama bin laden's hard drive. was one of them ilyas kashmiri, a top al qaeda leader? >> first of all, not sure that's been confirmed so it would be premature to begin assessing that until we actually know that ilyas kashmiri who has been a very important operational coordinator for al qaeda, whether he is, in fact, dead or not. >> and pakistan, what will be the sign to you it's really different? >> i think things change slowly in pakistan and we have to work our way through that. >> what about the death of bin laden, which gates said could be a game changer? what did you say the moment it was confirmed? >> i actually didn't say anything. we got the word and just basically did this and that was it. i don't think there's a lot of chest beaters in this particular business. >> signs that it is a game changer? >> not yet. certainly not here in afghanistan. it's really just too soon to tell. you know, it's only been a month. >> now these two men, lions in summer, fall and winter, are heading home. general petraeus had something for his friend, renowned for breaking the back of the bureaucracy to get what the troops needed to protect them. it's a piece of an armored vehicle called an mrap. it has a hole in it. he wanted gates to know, despite the power of the explosive, that vehicle gates had ordered had saved all the lives inside. >> even though there's a hole in this, the four individuals, the four troopers in this mrap, survived. pretty awesome, huh? >> we had a chance to spend some time with some troops on our trip this weekend who told us about what they think about whether we're winning, and how they miss just the smell of a freshly mown lawn. we want you to meet two people unlike any other. the only team of journalists to embed for one solid year on the front line with the troops here. and not only that, they're father and son. they're mike and carlos boettcher. we ask you, mike, just to give us a sense of what it's like out there in the hills at night when the darkness begins to fall? >> it's tough out there in the mountains. we met the troops in a makeshift chapel and there they spoke from the heart. one day, one mission, six months ago keeps coming back to me. american troops risking enemy fire to carry a badly wounded afghan soldier to a medevac. what i saw and can't forget tells me this -- they desperately want for him what they also want for his country -- for both to survive. a lot of american and afghan blood was spilled in this surge year. >> a jug of hme this big can take a man's leg off. >> reporter: lieutenant colonel david flynn's battalion was one of the hardest hit, as they fought bullets and thousands of homemade bombs to take the taliban's heartland, the arghandab valley. >> you can see this is a big job. >> boy, no kidding. [ gunfire ] >> reporter: my son and i ran for our lives when insurgents ambushed us at 9,000 feet in eastern afghanistan. but the 101st war squadron fought back -- hard, saving us and each other for a reason. >> coming here and just running around and killing the enemy and then leaving and looking back and saying "i didn't make a difference, i didn't make a change," will cause us to never to leave. >> reporter: for american sacrifice to mean something, they have to mean something, the fledgling afghan army and police. success, if it ever comes, is afghans fighting for afghanistan. but first they have to believe in their country and themselves. on this patrol, near the pakistan border last winter, they ran down the mountain, not up the mountain, towards the taliban. it was the 101st who moved to engage the enemy. american soldiers are trying to teach them by example. we saw it ourselves. a few weeks ago, surrounded by taliban on a mountainside and six of their buddies dead, the 101st kept pressing forward and the afghan army finally fought with them. a few days after that horrific nine-day battle, soldiers came to us, asking to speak about buddies who died. they wanted to tell us why. >> he did that for you. he did that for me. he did that for his family back home so that the fight stays here. >> reporter: they've given their best here, whether fighting to save an afghan soldier's life or just fighting for the soldier to the right and left of them. all they want is for it to mean something. >> again, father and son, mike and carlos boettcher. >> keep in mind, diane, many of these soldiers are 18 years old, 19 years old, and spent their formative years living in a state of war. >> virtually their entire adult life, as you were telling me before. i know it's been a year of living dangerously for you and them. we wish you and them great safety. >> we'll take care of him. >> -- out there. we'll be back with more from afghanistan. including what secretary gates said we have never heard a public official acknowledge before. but there is other breaking news of this day. and for that, we'll head back to new york where george stephanopoulos is standing by. george. >> thanks, diane. right here in new york a bizarre political scene late this afternoon. democratic congressman anthony weiner, after days of hedged denials and combative interviews about his internet photo scandal, called a press conference to reverse course. admitting to a long list of lies. apologizing to a long list of people. but the congressman refused to resign. "20/20" anchor chris cuomo has the exclusive interview that set this all in motion today. >> reporter: after a week of denial, today, a tearful anthony weiner said he will not resign but admitted he had lied and had, in fact, sent out inappropriate pictures and had inappropriate online communications with as many as six women. >> i have made terrible mistakes that have hurt the people i care about the most and i'm deeply sorry -- >> reporter: and weiner went so far as to admit the name of one of the women. was megan broussard one of the women? >> megan broussard was one of the women. >> he said, i'm an open book, maybe too open. >> reporter: 26-year-old megan broussard of texas says she first became acquainted with weiner on april 20th, after seeing this video online and commenting on his facebook page it was hot. now, what does that mean? >> i like to see someone who actually stood for something and was passionate about something. >> reporter: broussard says weiner immediately responded to her facebook comment. what she says soon followed was a flirtatious internet relationship, including, she claims, over 100 instant messages and eventually pictures. >> he was eager to hear if i wanted him, or thought he was attractive, or that sort of thing. >> reporter: how much of it was sex talk? >> i mean, he would attempt all the time. >> reporter: broussard says the two began exchanging a series of increasingly risque photos. broussard sent these, which abc has licensed from her. in return, she says she got the controversial photo from last week, as well as this bare-chested photo of weiner with photos in the background showing his wife and the clintons. she also says she received an explicit photo of a man's exposed private parts. when you got that photo, what did you think? >> i just thought it was risky. >> reporter: do you think he's a bad guy? >> no, i don't think he's a bad guy. i just think he's got issues. just like everybody else. >> reporter: but today he did something most people never have to do. he apologized in front of the media, especially to the person he says he hurt the most, his wife, who is an aide to secretary hillary clinton. >> my wife is a remarkable woman. she's not responsible for any of this. >> reporter: when broussard decided to come forward, a friend funneled her to andrew breitbart, the conservative blogger. he passed her name along to us. and weiner made clear today this is not a right wing conspiracy. he took full responsibility. that said, it isn't over, george. >> far from over, chris. in fact, the democratic leader in the house, nancy pelosi, has called for an ethics investigation. weiner said he's going to cooperate. still ahead on "world news," a remarkable medical breakthrough that could change the way we fight cancer. and later, back to diane sawyer in afghanistan, and what the children of afghanistan want to say to all of us. ♪ ♪ ♪ ♪ introducing purina one beyond a new food for your cat or dog. introducing purina one beyond what helps keep her moving? 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>> yeah, and just about every type of cancer there is, doctors are doing studies to see whether this approach will work. and once they understand what makes that cancer tick, doctors say we'll no longer be talking about breast cancer and colon cancer, we'll be talking about cancer from this mutation or that mutation. it's incredible because this will save lives. >> boy, that is promising news. rich besser, thanks very much. we have some news tonight about our abc family. it's official, katie couric is joining the network. she'll produce and host a daytime talk show that launches next year. and join our team here at abc news this summer. it is a homecoming for katie. she started her career here at abc news as a desk assistant in 1979. welcome back, katie. coming up, back to afghanistan and diane sawyer. óó [ male announcer ] this is lara. her morning begins with arthritis pain. that's a coffee and two pills. the afternoon tour begins with more pain and more pills. the evening guests arrive. back to sore knees. back to more pills. the day is done but hang on... her doctor recommended aleve. just 2 pills can keep arthritis pain away all day with fewer pills than tylenol. this is lara who chose 2 aleve and fewer pills for a day free of pain. and get the all day pain relief of aleve in liquid gels. look at all this stuff for coffee. oh there's tons. french presses, espresso tampers, filters. it can get really complicated. not nearly as complicated as shipping it, though. i mean shipping is a hassle. not with priority mail flat rate boxes from the postal service. if it fits it ships anywhere in the country for a low flat rate. that is easy. best news i've heard all day! i'm soooo amped! i mean not amped. excited. well, sort of amped. really kind of in between. have you ever thought about decaf? do you think that would help? yeah. priority mail flat rate shipping starts at just $4.95, only from the postal service. a simpler way to ship. is non-stop to seattle? just carry new preparation h totables. discreet, little tubes packed with big relief. from the brand doctors recommend most by name. new preparation h totables. the anywhere preparation h. we had a chance to talk a little more about life and lessons learned along the way with secretary gates. as we rode in with him on a big and -- as you'll hear -- somewhat noisy plane, it's also his command center. the man who held so much power in public life still thinks of himself as a kind of eagle scout from kansas. he has served eight presidents in both parties. and all have said he's the kind of man you can count on. the midwestern kid whose mother is still a roaring 98 and whose dad sold auto parts. the kid from wichita -- >> yeah, and i actually over the years i would still pinch myself. i came from a family of modest means. my brother and i are the first college graduates in our family's history. >> what did your dad think? >> actually, that's one of the few regrets that i have, my dad did not live to see me become director of cia or the president of texas a&m or secretary of defense. but our family is confident he's looking down, has seen it from a different perspective. but i miss dad. >> he says it was his dad who taught him to take responsibility. what about the men and women he ordered into battle in afghanistan? do you know how many have died since you became secretary of defense? >> as of yesterday, 1,255. and about 11,000 wounded. >> a personal note for every family. and before he writes, he reads and looks at the pictures. and he admits now that only young men may have enough resilience. >> and i've become more cautious, first, because i always knew the unpredictability of military conflict. and so often when the war drums are beating, everything is made to look simple and clean. we'll do this for a few weeks and we'll be done and we'll be over, it will be over. and it almost never works that way. i go to the hospital and go to arlington. i see their family. so i feel the human cost. and that's why i told somebody the other day, maybe, in fact, it is time for me to leave, because these things have begun to weigh on me in a way that maybe i'm not as useful as i used to be. >> too cautious? >> yeah. >> how do you experience it when you're home at night? >> well, that's when i do the condolence letters. >> and it's just too much? >> yeah. it's time. >> as someone said, genius is knowing when to stop. and by the way, the plane we rode in on, it's called the doomsday plane. it's the plane that takes survivors into the air in case of a nuclear attack. so what would life be like on board that giant command center? we'll give you a tour tomorrow. when we come back tonight, some kids we met in the streets of kabul who have a very big message. kids we he streets of kabul who have a very big message. when your eyes are smiling... you're smiling. and when they're laughing... you're laughing. be kind to your eyes... with transitions lenses. transitions adapt to changing light so you see your whole day comfortably... and conveniently while protecting your eyes from the sun. ask your eyecare professional which transitions lenses are right for you. i'm friend, secret-keeper and playmate. do you think i'd let osteoporosis slow me down? 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[ male announcer ] you should not take reclast if you're on zometa, have low blood calcium, or kidney problems. or if you're pregnant, plan to become pregnant or are nursing. take calcium and vitamin d daily. tell your doctor if you develop severe muscle, bone or joint pain, if you have dental problems, or if you develop new or unusual pain in your hip, groin, or thigh. the most common side effects include flu like symptoms, fever, muscle or joint pain headache, nausea, vomiting and diarrhea. share the world with the ones you love! and ask your doctor about reclast. once-a-year reclast. year-long protection for on-the-go women. finally tonight, i've come to afghanistan so many times and i think it's hard for those of us back home in america to imagine daily life here for the afghan people and for the troops who continually talk about the sweltering heat, the dust storms that blind you and actually coat your teeth. and for the afghans, keep this in mind, the average life-span here is 44 years old, and yet everywhere you walk, you find dreams exactly like ours. walking toward the marketplace in kabul, we saw two little boys going home right after school. hello! how are you? >> i'm fine, how are you? >> reporter: they said they love america and knew i was american too. how do i look american? >> you have hair like american. >> reporter: so, i ask about their country so long at war, if they think finally the u.s. is winning against the taliban. many of them said excitedly yes. and there'll be peace soon, you're sure? >> yes. >> reporter: after that, they sang a little and told me about their favorite movies in the whole world. >> "spider-man," "batman." >> reporter: "spider-man" and "batman." >> james bond. >> reporter: james bond. and as we started to leave, they said how wonderful it is that america wants afghanistan to be strong and happy too. >> hello america! >> reporter: and then as we walked away, something that seemed especially poignant, one little voice in the crowd said, i will miss you. i will miss you too. thank you. good-bye. and so on this night, when america is contemplating very big decisions, from kabul, afghanistan, for all of us at abc news, good night. h >> she lost her three month old baby in a gang-related shooting. police say it was a case of mistaken identity. >> tonight the san francisco firefighter copes with a double trag doe. >> bay area city putting cameras . gives a new meaning to neighborhood watch. >> and winery with a military motiff and a safe haven for local veterans. >> they killed my baby. they killed my soul, too . >> a young mother mourns the loss of an innocent infant. three month old baby killed over the weekend in what police believe is a gang-related shooting. it appears the wrong family was targeted with the senseless shooting. these are the police sketches of the men responsible. one suspect isurped arrest for the shooting. karina has more from east palo alto. >> right, the two suspects in the case are juveniles. police are not releasing their names. in addition police recovered three handguns which they