Is America's old fear of Communism the reason why the nation is afraid of atheists today?

This thought occurred to me yesterday when I was discussing the links between atheism and communism with a friend. In the past, to declare oneself an atheist in the US would have created the automatic assumption that one is also a communist (even if it wasn’t true, people would tend to jump to that conclusion). Now I don’t think people consciously make that connection today, but could this explain why America seems so afraid of atheists whereas European nations are not?