The Democratic Party has a broad and diverse religious coalition — which, as Laura Bronner and I wrote last week, can be challenging for any candidate hoping to use religious rhetoric to rally voters. But what, might you ask, about the Democrats who aren’t religious?

People who identify as atheists, agnostics or “nothing in particular” accounted for 35 percent of Democratic primary voters in 2016, according to the Cooperative Congressional Election Study,1 and as we mentioned in our article, are a growing constituency within the Democratic Party. And according to crosstabs from Morning Consult’s weekly tracking poll for May 20-26, support for Sen. Bernie Sanders is higher among religiously unaffiliated voters than among religiously affiliated voters. Former Vice President Joe Biden, meanwhile, has an edge among religious Democrats.

...At this point in the primary, religiously unaffiliated Democrats seem more open to a candidate who isn’t Biden than their religious counterparts. And while there is some variation in the level of support for Biden, he’s the clear front-runner among several major religious groups. Among nonreligious Democrats, though, Biden is less of a clear favorite. Instead, a plurality (30 percent) of atheists prefer Sanders, while agnostics are split between Biden and Sanders. And although Biden is the favored candidate of 32 percent of Democrats who say they’re “nothing in particular,” nearly one-quarter support Sanders. Meanwhile, Sen. Elizabeth Warren is also somewhat more popular among atheists and agnostics than she is among other religious groups.

...So for the time being, the religiously unaffiliated may remain a largely invisible group within the Democratic Party. But it’s worth watching how this group’s allegiances shift over the course of the primary — because as the number of nonreligious Democrats continues to grow, candidates may need to start figuring out strategies for how to appeal to them more directly.