To effectively combat Christian nationalism, you must first be able to see it and name it. These books provide valuable insights into this political ideology while also emphasizing the importance of religious freedom. (I don't love linking to Amazon, but they seem to be the only ones who show all of these available to order. Please feel free to order from somewhere else if you can find them.)
Sometimes an article just nails it, especially when it addresses complex issues like Christian nationalism, which intersects with various political ideologies and the ongoing conversation about religious freedom.