Was religion and politics linked in any ways in the late 19th century?

We are doing a debate in my AP English cl on whether the book Huck Finn should be banned. Since Mark Twain uses satire to mock religion, we need a reasoning as to why he did that. He, of course, thought that organized religion was bad, and that logical reasoning was better. But why did he think religion was bad? What it because religion influenced politics? This can hopefully turn into an argument we can use against our opponents. Thank You! Sources would be helpful.