Representative Bob Goodlatte. / Photo: Internet Education Foundation, Flickr Creative Commons

The United States Congress is about as Christian but more Catholic than it was 50 years ago, according to a recent Pew Research Center study.

In their “Faith on the Hill” report released Tuesday, Pew delves into the religious makeup of the 115th Congress, which took office the same day. Of the 535 members of Congress, 485—or 91 percent—self-identify as Christian. This percentage has barely shifted since 1961, when 95 percent of Congress identified as Christian.

The biggest changes in the religious makeup of Congress have been denominational shifts. Mirroring the general population of Americans, the Catholic denomination is on the rise. While Protestants (56 percent) still outnumber Catholics (31 percent) in Congress, the 115th Congress has seven fewer Protestants and four more Catholics than the 114th Congress.

Pew spokespersons wondered, however, why the religious makeup of Congress has shifted so little considering the significant changes in the American religious landscape over the past half-decade. Only 71 percent of Americans describe themselves as Christian, while the religiously unaffiliated make up nearly a quarter of American society. Why, then, is there only 1 Congressperson—or .2 percent of Congress—who identifies as non-religious?

“One possible explanation is people tell us they would rather vote for an elected representative who is religious than for one who is not religious,” said Greg Smith, associate director for research at Pew. “Being a nonbeliever really is a political liability.”

Analysts believe, however, that it is slowly becoming easier to campaign for public office as a non-Christian. Casey Brescia, communications associate for the Secular Coalition of America, told Religion News Service that while there is a price for running as a non-religious candidate, “it’s not nearly as significant as it as in the past, and it’s not nearly as prohibitive.”

The shift is happening faster among Democrats. While Democrats in Congress remain “overwhelmingly” Christian at 80 percent, they have more religious diversity than Republicans in Congress, 99.3 percent of whom are Christian. Indeed, of the Republicans in the 115th Congress, only two are not Christian.

For The Atlantic’s Emma Green, the solution to changing the religious makeup of Congress is simple: the non-affiliated need to vote.

“Even though the religiously unaffiliated share of the American population has significantly increased from 14 to 22 percent between 2004 to 2014, the share of religiously unaffiliated voters only increased from 9 to 12 percent,” Green said.

“If this is truly a crisis of representation, there’s good news. Religiously unaffiliated Americans who are bothered by their lack of a voice in Congress can use one simple trick to start making change: They can vote.”

Among the non-Christians currently serving in Congress, 25 are Jewish, 2 are Buddhist, 2 are Muslim, and one is Hindu. The 115th Congress, only 19 percent of members are women and 20 percent of members are non-white.

—by Caroline Matas