When Americans are asked to check a box indicating their religious affiliation, 28% now check 'none.'

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%).

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