Disheartening new research shows that political beliefs are increasingly determining whether someone goes to church. While politics is keeping Republicans in the pews, it’s driving Democrats away. To bring them back, Republicans and pastors have to step up.

In an op-ed last week in the New York Times, University of Pennsylvania Assistant Professor Michele Margolis details the bleak picture. Most people determine their political affiliation before their religious community, and politics becomes an important factor in whether or not they go to church. While we typically assume the already-religious are drawn to the GOP, polling data that tracked people over decades found that members of the two parties started out equally religious, but Democrats left the church.