NEW YORK — For the first time in its history, the United States does not have a Protestant majority, according to a study. One reason: The number of Americans with no religious affiliation is on the rise.
The percentage of Protestant adults has reached a low of 48 percent, the first time that the Pew Forum on Religion & Public Life has reported with certainty that the number is below 50 percent. The drop, long anticipated, comes at a time when no Protestants are on the Supreme Court and Republicans have their first presidential ticket with no Protestant nominees.
One factor is the growth in nondenominational Christians, who can no longer be categorized as Protestant, and a spike in the number of adults with no religion. The study, released Tuesday, found about 20 percent of Americans say they have no religious affiliation, up from 15 percent in the last five years.
Scholars debate whether people who say they don’t belong to a religious group should be considered secular. The category as defined by Pew includes atheists but encompasses majorities of people who say they believe in God, and a notable minority who pray daily or consider themselves spiritual but not ‘‘religious.’’
Pew found that most of the unaffiliated aren’t seeking another religious home.
Growth among those with no religion has been a preoccupation of American faith leaders, who worry that the United States, a highly religious country, would go the way of Western Europe, where church attendance has plummeted. This week in Rome, Pope Benedict XVI is convening a three-week assembly of bishops aimed at bringing back Roman Catholics who have left the church.
Voters who describe themselves as having no religion vote overwhelmingly for Democrats. Pew found they support abortion rights and gay marriage at a much higher rate than the public at large. They are an increasing segment of voters who are registered as Democrats or lean toward the party, growing to 24 percent over the last five years from 17 percent. The religiously unaffiliated are becoming as important to Democrats as evangelicals are to Republicans, Pew said.
The analysis, done with PBS’s ‘‘Religion & Ethics Newsweekly,’’ is based on several surveys, including a poll of nearly 3,000 adults. The finding on the Protestant majority is based on responses from a larger group of more than 17,000 people and has a margin of error of plus or minus 0.9 percentage points.
The spread of secularism in Western Europe was often viewed as a byproduct of growing wealth. Yet among industrialized nations, the United States stood out for its religiosity. Now, scholars say the decreased religiosity could reflect a change in how Americans describe their religious lives. In 2007, about 60 percent of people who said they seldom or never attend religious services identified themselves as part of a particular religious tradition. In 2012, that fell to 50 percent.