Lisa I believe that Christianity itself would naturally lean right. Certainly this could be reflected in the society that the USA had when it was predominately a Christian country.
However like every other important institution in the West, communists have targeted churches, infiltrated them, and introduced left wing propaganda in them. Every important institution and important influence in American society has been infiltrated and corrupted. Marriage, Schools, Government, Movies, Television, Art, Books, Music, Newspapers, Magazines, and yes Churches too.
That's why most "main line" protestant churches are now corrupted. Even so-called evangelical churches are now being corrupted although there are still some good ones. More traditional Christians may end up having to meet in each other's homes if it keeps going the way it's going.
I don't want people to think this is something endemic to Christianity. It's a deliberate infiltration from the outside by atheists, pagans, and communists.