DON'T EXPECT any official "Atheists for Hillary" outreach, but political progressives are cheered by a study showing a rise in the number of nonreligious Americans.
It's not because top Democrats are irreligious; both President Obama and Hillary Clinton are persons of faith. But liberals welcomed the findings of the 2014 Religious Landscape Study, released last week by the Pew Research Center, which showed a country growing less religious.
Republicans consistently do well among voters with strong religious beliefs, and Democrats score better with voters who don't express religious views.
The huge study - a 35,000-person sample - reveals that over the past seven years, there has been a 10 percent decline in self-identified Christians, though they still are more than 70 percent of the population. At the same time, the religiously nonaffiliated, or "nones," have increased by about one-third and now account for about 23 percent of American adults.
This trend could have political implications.
Evangelical Protestants, the core of the Republican base since Ronald Reagan, have held steady over the past seven years, according to the study, though their share of the population has declined somewhat. In the last presidential and midterm elections, evangelicals made up more than a quarter of the electorate and voted Republican 4-1.
The number of Catholics also has declined slightly. They are about a quarter of the electorate and constitute a political swing group. White Catholics vote Republican, their nonwhite counterparts are mainly Democrats.
The growth of the "nones" - designating "people who self-identify as atheists or agnostics, as well as those who say their religion is 'nothing in particular,' " is most pronounced among younger Americans. More than a third of millennials - 18- to 33-year-olds - have no religious affiliation. A quarter of whites are unaffiliated religiously, along with 20 percent of Hispanics and 18 percent of blacks.
There is a debate over the direct political effects.
"We have not yet felt the impact of the religiously unaffiliated at the ballot box," said Robert P. Jones, chief executive officer of the Public Religion Research Institute. The "nones," he said, register and vote less than committed Christians.
David Campbell, a political scientist at the University of Notre Dame and co-author of American Grace: How Religion Divides and Unites Us, believes that continuing efforts by conservative factions on gay rights and issues that they consider matters of religious freedom will galvanize the nonreligious.
"The single greatest mobilizing force for secularists is the religious right, especially among millennials," Campbell said.
Political leaders of the evangelical movement don't dispute Pew's findings, but question the implications. They argue that the ascendancy of nonbelievers would energize their base on issues ranging from same-sex marriage to the "war on Christmas," and even, for some, mixed-religion marriage.
Moreover, they doubt that the unaffiliated can coalesce behind any agenda.
"Secular voters are simply harder to organize because unbelief historically is not as animating in terms of political engagement as deeply held religious faith," said Timothy Head, executive director of the conservative Faith and Freedom Coalition.
With two polarizing camps playing off each other, faith may become like Congress: dominated by the wings with little room in the middle.