Christian conservatives are reeling not only from the loss of the presidency but from what many of them see as a rejection of their agenda. They lost fights against same-sex marriage in all four states where it was on the ballot, saw anti-abortion-rights Senate candidates defeated and two states vote to legalize marijuana for recreational use.

It is not as though they did not put up a fight; they went all out as never before: The Rev. Billy Graham dropped any pretense of nonpartisanship and all but endorsed Mitt Romney for president. Roman Catholic bishops denounced President Barack Obama’s policies as a threat to life, religious liberty and the traditional nuclear family. Ralph Reed’s Faith and Freedom Coalition distributed more voter guides in churches and contacted more homes by mail and phone than ever before.

“Millions of American evangelicals are absolutely shocked by not just the presidential election but by the entire avalanche of results that came in,” R. Albert Mohler Jr., president of the Southern Baptist Theological Seminary, in Louisville, Ky., said in an interview. “It’s not that our message — we think abortion is wrong, we think same-sex marriage is wrong — didn’t get out. It did get out.

“It’s that the entire moral landscape has changed,” he said. “An increasingly secularized America understands our positions and has rejected them.”

The election results are just one indication of larger trends in American religion that Christian conservatives are still digesting, political analysts say. Americans who have no religious affiliation — pollsters call them the “nones” — are now about one-fifth of the population overall, according to a study released last month by the Pew Forum on Religion and Public Life.

The younger generation is even less religious: About one-third of Americans ages 18-22 say they are either atheists, agnostics or nothing in particular. Americans who are secular are far more likely to vote for liberal candidates and for same-sex marriage. Seventy percent of those who said they had no religion voted for Obama, according to exit polls conducted by Edison Research.

“This election signaled the last where a white Christian strategy is workable,” said Robert P. Jones, chief executive of the Public Religion Research Institute, a nonprofit, nonpartisan research and education organization based in Washington.

“Barack Obama’s coalition was less than 4 in 10 white Christian,” Jones said. “He made up for that with not only overwhelming support from the African-American and Latino community, but also with the support of the religiously unaffiliated.”

In interviews, conservative Christian leaders pointed to other factors that may have blunted their impact in this election: They were outspent by gay rights advocates in the states where marriage was on the ballot; comments on rape by Senate candidates Todd Akin in Missouri and Richard Mourdock in Indiana were ridiculed nationwide and alienated women voters; and they never trusted Romney as a reliably conservative voice on social issues.

However, they acknowledge that they are losing ground. The evangelical share of the population is both declining and graying, studies show. Large churches like the Southern Baptist Convention and the Assemblies of God, which have provided an organizing base for the Christian right, are losing members.

“In the long run, this means that the Republican constituency is going to be shrinking on the religious end as well as the ethnic end,” said James L. Guth, a professor of political science at Furman University in Greenville, S.C.

For the Christian right in this election, fervor and turnout were not the problem, many organizers said in interviews. White evangelicals made up 26 percent of the electorate — 3 percent more than in 2004, when they helped to propel President George W. Bush to re-election. During the Republican primaries, some commentators said that Romney’s Mormon faith would drive away evangelicals, many of whom consider his church a heretical cult.

And yet, in the end, evangelicals voted overwhelmingly for Romney.

“We did our job,” said Reed, who helped pioneer religious voter mobilization with the Christian Coalition in the 1980s and ’90s, and is now founder and chairman of the Faith and Freedom Coalition.