This is all true to an extent (though an incumbent President can loose, but they do have a solid advantage).
But we are also a nation which has a fundamentalist minority that drives the election process of one of our two major parties.
They aren't the Christian Taliban because the Taliban was actually in power, so could do what it wanted. The difference is these people can't. That doesn't mean they don't want to.
These people would be happy to criminalize sex that didn't conform to their view of Correct (all the while preaching of "personal liberty" and "freedom"). They would not stone the woman for being raped, but they'd call her a whore who asked for it because she didn't dress appropriately. They would teach only what is religiously acceptable in schools, including mandating prayer (except for the Jews, who are the only ones who would not have to go). They would go back to segregation at best (if not outright slavery, which was also in the bible).
Fortunately, most Americans are not this vile. Even most Republicans. Unfortunately, this minority has enthusiasm and a will-to-power like no one else, so is always out there on election day, always donating, always working -- so the Republicans have to kowtow to them. There is a certain subset of their beliefs-- fiscal conservatism-- which resonates with a lot of the sane Republicans, and a lot of moderates (and even some Democrats), and so lately they've been trumpeting that and getting a lot of support in the "Tea Party" movement.
But their fundamentalism, the ultimately theocratic Republic they actually want, the "social conservatism" that almost everyone outside of their minority rejects, is never very far away. They just don't say it too loud, and say only the least bigoted things they can get away with. Currently, homophobia is the most socially acceptable form of bigotry, so they're all about that.
That doesn't mean they wouldn't put the blacks in their place if they could. They are just sane enough to keep that talk mostly quiet (but its quite telling when someone brings a mic to rallies...).
Alas. Our parties are engines for elections more then ideological political groupings, and this minority has rooted itself very deeply into the engine of one of the them. That's scary as all hell, but they are a long way to becoming the Christian Taliban. That doesn't mean they don't *wish* they had that power.
Most Christians by far are still fair-minded, decent people who may even disagree with things like homosexuality and even vote against gay marriage -- but they don't long for the day before Lawrence vs Texas was ruled when gay sex was an actual crime. There's a huge difference between Fundamentalist Christianity and mainstream Christianity. Just like there's a huge difference between Fundamentalist Islam and mainstream Islam.
The fundamentalists in the Christian world are just not in actual power. (Thank God. History tells us what happens when they do get in power).