coming up -- we revisit the 20% of americans who say they have no religious affiliation. and kim lawton reports on the ongoing standoff between the vatican and american nuns. welcome, i'm bob abernethy. it's good to have you with us. at the vatican, the college of cardinals is making preparations for the selection of the next pope now that benedict xvi has officially stepped down, the first pope to do so in over 600 years. on thursday, his final day, benedict met with the cardinals already gathered in rome and promised "unconditional reverence and obedience" to his successor. he then took a helicopter to the papal villa, castel gandolfo, where he will stay until moving to a vatican monastery for what he's said will be a life of prayer outside of public view. during his last papal audience on wednesday, benedict spoke of the joy of leading the church, as well as the many difficulties he faced a pope. >> i will continue to accompany the church with my prayers and i ask each of you to pray for me and for the new pope. with the papal seat empty, the cardinals will soon decide when to begin the conclave to elect their next leader. earlier this week, cardinal keith o'brien of scotland, who recently resigned because of age, announced he would not attend the conclave, after charges against him by other priests of "inappropriate" behavior. american cardinal roger mahony will participate, despite objections from some american catholics over mahony's role in covering up clergy sex abuse. all cardinals under the age of 80 can cast ballots for the next pope, who is selected by a vote of at least a two-thirds majority. meanwhile, the 77-million-member anglican communion is also getting a new leader. later this month, justin welby will take his seat as the new archbishop of canterbury, spiritual leader to anglicans and episcopalians around the world. kim lawton was in the u.k. this week and spoke with welby about this important moment in these two christian traditions. >> reporter: at the historic coventry cathedral, archbishop justin welby was attending a conference this week about faith and reconciliation. welby told me he's watching the events in rome closely. he says he believes catholics and anglicans have much in common, despite their sometimes tense relationship. >> we have major differences over the ordination of women, things like that. we have historically different understandings of the nature of the church, the authority of the church. but we have a common basis around the need to proclaim the good news of jesus christ. >> reporter: he says he hopes dialogue between the two will continue to grow. welby will be enthroned as the next archbishop of canterbury on march 21, when he officially takes the helm of one of the largest bodies of christianity. the former oil-executive-turned-clergyman acknowledges it's interesting that the anglican communion and the roman catholic church will both have new leaders within the next few weeks. >> i don't read too much into it. benedict xvi was a very remarkable, has been a remarkable pope. he took over at the age of 78, not the age most of us would want to take on a new task, and he gave himself, spent himself almost. but i do look forward very much to meeting the new pope later in the year, and i'm confident we'll find in each other a common love for christ. >> reporter: archbishop welby says he hopes to attend the inallati ceremony for the new pope in rome depending on when it takes place. i'm kim lawton in england's coventry cathedral. >> we'll have more of kim's interview with the new archbishop of canterbury in coming weeks. in other news, in washington, as the so-called sequester neared, a coalition of close to one hundred christian leaders urged congress to prevent cuts to poverty programs from going into effect. in what they described as a pastoral letter, the leaders, both liberal and conservative, called for an end to political brinksmanship which they said has prevented a "sound and moral path" to fiscal sustainabity. the group acknowledged congress had agreed to protect certain programs that help low-income americans, but they said more needs to be done to reduce hunger and poverty. advocates on both sides of the gay marriage debate have filed briefs in two highly anticipated supreme court cases. later this month, the court will hear arguments on proposition 8, california's ban on gay marriage and on the federal defense of marriage act, which defines marria as tween a man a a man. this week, this obama administration as well as several dozen prominent republicans, including many from the bush administration, filed briefs in support of gay marriage and opposing the california ban. religious groups have also filed briefs both in favor of and against gay marriage. meanwhile, outside the court on wednesday, civil rights and some faith organizations urged the justices to strike down a challenge to the voting rights act. > aordin to rece surveys there has been a steady increase in the number of people in this country who say they have no religious affiliation at all. pollsters call them the nones, n-o-n-e-s, because when they are shown a list of religions and denominations, and asked which one is theirs, they say, in effect, none of the above. last fall we did a well-received series on the nones, who they are, what they believe, and we want to revisit those stories today and in the next two weeks. our partner in theeriewas the pew forum on religion and public life, where greg smith is a senior researcher. >> almost one in five american adults, 20%, describe themselves as religiously unaffiliated. that equates to about 46 million adults in the united states, so this is a big, growing, important group in american society. to see its continued growth at this kind of rapid rate has been very striking. >> striking indeed. in the early 1990s just under 10% were unaffiliated. since then that number has doubled. about 13 million are atheists and agnostics. 33 million more describe their religion as "nothing in particular." by education and income and other common measurements, the nones are very much like americans as a whole. except for age. >> about one-third of all american adults under the age of 30 describe themselves as either atheists or agnostics or say they just don't have any particular religion. and that large number is a big part of what's driving the overall grow in this population. >> being unaffiliated means not being a member. it does not mean being a nonbeliever or being hostile to religion. indeed, many nones have kind words for places of worship. >> they say that religious organizations are effective in providing help to the poor and to the needy. they say religious organizations do a good job of helping bring communities together. >> two-thirds of the unaffiliated say they believe in god, or a universal spirit. more than a third, 37%, call themselves spiritual but not religious. about one in five say they pray every day, and the same number say religion is at least somewhat important in their lives. with all that religiosity, then, why do 46 million americans say they are unaffiliated with any religious organization? >> they tend to be much more likely than the public as a whole, for example, say that religion and religious organizations are too focused on rules, too concerned with things like money and power,too cuseon pitics. >> we spoke with several young nones, among them rachel mariman, a junior in college who was raised in a very religious home. but during her senior year in high school, she says, she turned away from all religion. >> my church was actually pretty good, but i sort of just had issues with religion in general. young people are becoming increasingly willing to tolerate people who are different. to tolerate different sexual orientation, different religion, different ethnic background, whatever. we don't want to be told that we can't accept gay marriage or that we can't support birth control or abortion. you can still be moral and you can still be a good person without being religious. >> 27-year-old kellen mcclure describes himself as very spiritual. he believes in god and visits churches, but not for their worship services. >> i don't necessarily feel like i need to be guided through my relationship with, you know, the higher power or whatever you will call it. i feel like it's a very personal relationship and i dot necessarily need to be sitting in a church to experience that relationship. so that's why i've never really been drawn to attending services regularly. >> instead, kellen meditates, here in a basilica. >> being spiritual to me means reflecting that maybe i'm not just a biological creature. it means that there's something else and that something else could be a higher power, and it's that something else that connects us to each other. >> thank you very much for everything that we have. >> kellen says he gives thanks daily. >> every day my girlfriend and i sit down to dinner. i am insistent that we say a grace, and that grace is not necessarily a religious grace. it's just a moment that we can both sit there and reflect on how lucky we are. >> kellen also said one reason he does not go to church often is that sunday mornings are his only times to rest. >> we live very hectic lives. i work. i go to school. it leaves a very short amount of time to do things on my own free time. >> among religious leaders and social scientists, there are lots of theories about why there are so many nones. some say many people don't want to join anything, religious or otherwise. some think there's a general softening in religious belief and commitment. many of the nones say they want no part of the conservative politics some churches embrace. others say society in general has become much more tolerant of non-believers, so it's easier thait used to be for some people to acknowledge publicly what they have long been in private, to come out of the atheist or agnostic closet. >> many people of faith may be troubled by the findings in our survey. for instance, three-quarters of all the nones say they were raised in religious homes. very few of them say they are seeking a church that is right for them. they seem quite content to remain unaffiliated. indeed, for people in any age group, the percentage of unaffiliated when ty are young remains the same as they get old. >> i think that if i have children i think that's the same thing that i would like to teach them is that religion is important, being spiritual is important. what's not as important is to join and to go every week. >> however people interpret our survey, greg smith insists the results are snapshots, not predictors. >> while the number of religiously unaffiliated people is growing, it's also true that the vast majority of americans continue to be affiliated with a religion and that's even true of young pple. if one-third of young people are unaffiliated it means that two-thirds of them do continue to identify themselves as members of a religious faith. >> and if 20% of americans say they have no religious affiliation, that leaves 80% who do. one of many questions surrounding the soon to be selectenew pope is how he will handle the standoff between the vatican and many american nuns. last april, the vatican accused the umbrella group that represents the majority of us nuns of "doctrinal confusion." yet many of these sisters say they are just following the spirit of vatican ii, the landmark council convened in 1962 by pope john xxiii to make the catholic church more relevant to the modern world. kim lawton has this special report. >> reporter: in washington, d.c., sister maureen fiedler hosts the public radio program interfaith voices. she tries to broaden interreligious understanding in order to further justice and peace, values she says come straight from her roman catholic faith. >> this isn't something peripheral. this is central to the preaching of the gospel. >> reporter: fiedler entered religious life 50 years ago, just before vatican ii got underway. she says the spirit of the vatican meetings had a profound impact on how she viewed her calling. >> the second vatican council had a marvelous document called "the church in the modern world," which basically underlined the message of justice and peace in the gospel. >> reporter: fiedler became involved in a series of social justice causes, including a 37-day fast in support of the equal rights amendment and rallies in support of the ordination of female priests. >> it just all fit together as a piece for me, and it also fit together in my prayer as i tried to put this together with the second vatican council. it simply made sense to try to alleviate the suffering of the poor, to end wars, to overcome discrimination. that for me was christianity. >> reporter: but some critics say many catholic sisters have been using the second vatican council to justify positions and activities that are in conflict with official church teachings. colleen carroll campbell is a columnist and author. >> this idea that having this second vatican council and pronouncing that there's this amorphous spirit that gives us license to pretty much throw the baby out with the bath water, so to speak, when it comes to catholic doctrine-it's simply wrong, and i think we've heard over and over from pope john paul ii and pope benedict xvi that it's wrong. >> reporter: pope john xxiii convened the second vatican council in october 1962 in order, as he put it, to "open a window and let in a little fresh air." >> even though in the united states there were a lot of changes going on in the '40s and '50s after the second world war, in worldwide catholicism these changes really hadn't occurred. and so in order to open up a window for the whole church, not just in modernized countries, this council was called. >> reporter: over the next three years, church leaders at the council produced 16 documents on a host of topics, from introducing local languages into the mass to expanding lay involvement and promoting more interfaith dialogue. one of the documents focused on religious life. it encouraged catholic sisters to reexamine their mission, their rules, even their style of dress. >reporter: many u.s. siers began mofyinor en eliminating the traditional habit. the clothing changes for prioresses of the dominican sisters in amityville, new york, were dramatic. >> she says vatican ii urged people to get out of the city. >> i think that's one of the great gifts of vatican ii, that it sent us back to study what the gospels were saying, and er and over again it was about feed the hungry, visit those in prison, help the poor. >> reporter: the dominican sisters in amityville have a variety of ministries designed to help those at the margins, such as literacy classes to teach new immigrant women english. there are homes to help women and children with nowhere else to live, and there's even an organic garden, where about 20% of the produce is donated to an interfaith food network. under an umbrella organization called the leadership conference of women religious, or lcwr, many communities of nuns began shifting their ministries in the wake of vatican ii. fo some sisters, it was an exhilarating time. but others were concerned. >> there was a minority of women who didn't feel that the changes were appropriate, that the adaptations to modern life, the moving out of the parish into the world, that these movements had gone too far. >> reporter: some nuns became part of a separate organization that holds more traditional views. >> the vatican ii documents are a pretty straightforward read. i think the difficulty mes whenou don't read everything in context, perhaps. i would find it difficult to read the documents, then come up with them saying something more than what they say. >> reporter: the lcwr still represents about 80% of the some 57,000 american nuns. the group has increasingly taken on advocacy positions, including some that are controversial. >> these are the sisters that publicly stated to john paul ii that women should be ordained, that women should be allowed to work in all the ministries of the crch. this is the same organization that signed "the new york times" letter which said that there is a legitimate, diverse opinion on the question of abortion. >> reporter: sister mary hughes is immediate past president of the lcwr and still part of its leadership team. >> are there persons who have divergent opinions? i think that's true in the whole church. it's not just true in religious life. i think sometimes there's a concern if we raise a question that means that we are in defiance, and that's not at all what happens. but i think we're going to continue to raise the questions, because there might be areas that we would hope the church would look at. >> reporter: in 2008, vatican officials began an investigation into the lives and doctrine of u.s. women religious. this past april, the vatican released a report accusing the lcwr of having "serious doctrinal problems." the assessment specifically criticized the group for being largely silent on right-to-life issues, and it mandated that the group come under the authority of some us bishops. >> we're stuck with a situation that we are not happy about, that we answered all the questions that we're given to us in the doctrinal assessment honestly, carefully, prudently, and when we didn't hear back, i guess we thought that we were believed. and i think there are aspects of the mandate that make us wonder if our materials were read. >> reporter: for example, hughes says she believes there is more than one way to promote the sanctity of human life. she says her community's ministries against domestic violence and in support of homeless mothers and children is also prolife work. >> that's about the sanctity of human life. it's about doing it differently. i think it's complementary. i don't think you can have one without the other. >> we're talking about defending the sanctity of every human life from the cradle to the grave, defending the sanctity of marriage as the church sees marriage as the union of one man and one woman, and just generally promoting church teaching, and upholding that teaching and witnessing with joy to that, and that's not what many lay catholics have seen. >> reporter: professor mcdannell says since the death of john the xxiii church leaders have appeared to be consolidating authority. >> the new generation of men want a catholic church which is more traditional, which is more devotional, which is more willing to be obedient to the authority. >> reporter: some wonder if there is any room for dialogue and debate. >> this is not just about the vatican versus the nuns. this really is about the future of how we interpret the message of the second vatican council, and what's going on right now quite frankly makes me sad, because i see certain people in rome, in the vatican, who want retrenchment, who want to go back to the church the way it was before the second vatican council, when the church was essentially the hierarchy, and they determined everything down to sometimes the minutia of catholic life. >> women religious need to stand with the church, and if they don't feel that they can in good conscience do that anymore then i think it would take more integrity to simply step back and say, you know, maybe we're not called to be catholic women religious anymore. maybe we want to be something else. >> reporter: many lay catholics have been rallying in support of the sisters. hughes says they been getting letters of encouragement from across the country. she says she remains hopeful that, in the spirit of vatican ii, healing can prevail. >> there's always a blessing that comes with every conflict. perhaps the blessing is that we continue to open up within the church avenues for true dialogue and true dialogue isn't about winners and losers. it's about people truly being able to listen to understand the other perspective before making any judgments. >> reporter: i'm kim lawton reporting. on our calendar, this weekend, bahai's begin a 19-day fast. they abstain from food and drink between sunrise and sunset and practice prayer and meditation, the time of fasting leads up to the new year celebration, nowz. on wednesday, at the capitol in washington, the late rosa parks became the first black woman to be depicted in a full-length statue in statuary hall. park's refusal in 1955 to give up her seat on a segregated montgomery, alabama, bus led to a bus boycott that lasted more than a year and helped trigger the civil rights movement. >> and in a single moment, with the simplest of gestures, she helped change america -- and change the world. >> according to parks' biographer, her mother and grandmother taught her that part of being respected was to demand respect. parks died in 2005 at the age of 92. and, finally, doctor c. everett koop died this past week. he was a highly-respected pediatric surgeon appointed by president reagan in the early '80s to be surgeon general of the united states. koop campaigned vigorously against smoking, with considerable success. he wasan evangical presbyterian who surprised many by his vigorous efforts to address the hiv and aids epidemic through his advocacy of condom use and sex education. he was also a staunch opponent of abortion. dr. koop was 96 years old. that's our program for now. i'm bob abernethy. you can follow us on twitter and facebook and watch us anytime on the pbs app for iphones and ipads. there's much more on our webte. you can comment on all of our stories and share them. audio and video podcasts are also available. join us at pbs.org. as we leave you, scenes from the vatican of benedict xvi, now pope emeritus, during his final days as the successor to saint peter. major funding is provided by the lilly endowment dedicated to its founders interest in community education. additional funding provided by mutual of america designing custized, indivual d group retirement