A new study from Pew Research finds that the religiously unaffiliated – a group comprised of atheists, agnostic and those who say their religion is "nothing in particular" – is now the largest cohort in the U.S. They're more prevalent among American adults than Catholics (23%) or evangelical Protestants (24%).

Gregory Smith at Pew was the lead researcher on the study, titled "Religious 'Nones' in America: Who They Are and What They Believe."

He says the growth of Nones could affect American public life.

"We know politically for example," Smith says, "that religious Nones are very distinctive. They are among the most strongly and consistently liberal and Democratic constituencies in the United States."

And that could change electoral politics in the coming decades.

The political power of white Evangelicals has been well-reported in recent decades, but their numbers are shrinking while the number of the more liberal Nones is on the rise.

However, Smith points out that Nones are also less civically engaged than those who identify with a religion – they're less likely to vote. So, while they identify as Democrats, getting them to the polls on election day may prove to be a challenge.

Within the Nones, however, atheists and agnostics are MORE LIKELY to be politically and civically engaged, whereas those who responded that their religion is 'nothing in particular' are far less likely to vote.