As he ran for the White House, John F. Kennedy assured skeptical Americans that he was "not the Catholic candidate for president," but rather a "candidate for president who happens also to be Catholic." In 1961, the year he took office, Catholics accounted for 18.8% of Congress.
On Tuesday, when the 111th Congress is sworn in, about 30% of its membership will be Catholic, according to a recent analysis by Congressional Quarterly and the Pew Forum on Religion & Public Life. The shift reflects greater religious diversity both across the nation and on Capitol Hill.
"We see much more acceptance of religious groups that have in the past . . . suffered some prejudice," said David Masci, a senior research fellow at the Pew Forum and coauthor of the report.
Catholics, at just less than 24% of the U.S. population, have gained more congressional seats since 1961 than any other religious affiliation, the report found. At 1.7% of the population each, Jews and Mormons make up 8.4% and 2.6% of Congress, respectively.
When Kennedy was elected, Protestants accounted for most of Congress -- 74.1%. Though their numbers have declined, they still form a majority at 54.7%, slightly higher than their 51.3% of the population.
Since the 87th Congress was seated in 1961, many major Protestant denominations have slipped in numbers, including Methodists, at 10.7% now and 18.2% then; Presbyterians, at 8.1% compared to 13.7%; and Episcopalians, who dropped to 7.1% from 12.4%. But when compared to the population, these three denominations still are overrepresented on Capitol Hill.
Yet other Protestant denominations are underrepresented: Baptists make up 17.2% of Americans but 12.4% of the House and Senate. Pentecostalists are 4.4% of the population but 0.4% of congressional lawmakers.
Slightly underrepresented are Buddhists and Muslims: Two of each were first elected to the 110th Congress and return next term. The study can be found at pewforum.org.
Though the religious makeup of the new Congress generally reflects that of the nation, the report found that members of Congress are much more likely than the overall public to claim a religious affiliation.
Only five members of the incoming Congress -- about 1% -- declined to specify their beliefs for the survey. But because of how the question was worded, it was unclear whether the lawmakers were atheist or agnostic or simply didn't want to answer the question.
Masci said he hoped to refine studies in the future. For example, he would like to better distinguish between the various strands of Christianity.
Overall, studies conducted over the years have consistently shown Americans to be a people of faith. A Pew Forum report last summer found that 92% of Americans say they believe in God or a universal spirit. It's no surprise, Masci said, that most Americans want to elect politicians of faith.
"I think there's an incentive, certainly, for a politician to have some sort of a religious affiliation," Masci said. Americans, he said, have "a desire to have people in office who, to at least to some degree, reflect your own belief."
Yet a religious affiliation does not always correlate to a certain religious belief, said Woody Kaplan, chairman of the advisory board of the Secular Coalition for America.
Take Rep. Pete Stark: The Democrat from the Northern California city of Fremont identifies himself as a Unitarian but acknowledged no belief in a supreme being in 2007, making him the first member of Congress to publicly do so. Atheist groups said Stark was the highest-ranking elected official ever to admit he didn't believe in God.
Stark said in a recent interview that in the week following the announcement, he received more than 5,000 e-mails from around the world, nearly all congratulating him for his courage.
The reaction took Stark by surprise. Stark said he had simply filled out a survey sent by the secular coalition.
Stark, 77, said he was "agnostic at best" by the time he graduated from college in 1953, but his religious beliefs played little part in his first campaign for the U.S. House in 1972. His 13th District covers a variety of Bay Area cities, including Alameda, Union City and Hayward.
"In my district, it just didn't come up; nobody asked me," he said. "They didn't care much about what I did on Sundays."
Then in fall 2006, the secular coalition embarked on a quest for the highest-ranking non-theist public official in America. It offered a $1,000 prize to whoever identified the winner.
Nearly 60 members of Congress were nominated. The coalition sent them surveys, and Kaplan said that when he interviewed the lawmakers, 22 confided that they did not believe in a god. Fearful of exposure, all but Stark told the group to keep quiet.
"The perception is it's politically dangerous" to be godless, Kaplan said.
Indeed, a USA Today/Gallup poll in early 2007 showed that atheism would be a huge obstacle for a presidential candidate: 45% of respondents said they would vote for a nonbeliever, compared with 55% for a gay person, 88% for a woman and 95% for a Catholic.
For many Americans, "there's this idea of morality being linked to belief in God and to religion," Masci said. "Atheism is different in that it's a real departure from the common-denominator faith that at least most people accept."
But if more atheists, humanists, freethinkers and nonbelievers "come out," Kaplan said, "the stigma -- which is clearly there -- will begin to go away."
The evidence? Kaplan points to Stark. In November he was elected to his 19th term with 76.5% of votes.