I'm confused about the American Republican party

[Jester]

I never followed the Democrat primaries in the past, are they the same?

Yes and no. It's still not acceptable to be irreligious, even in the Dems. And there are some votes to be gained by courting religious interest groups, although the most fervent (the African-american evangelical churches) have more pressing social issues than religious conservatism.

However, this is nowhere near the scale of the Republicans, for whom the religious right represents a formidable voting bloc that can make or break candidates. They have unity of purpose and message, they donate heavily, and they come out to vote. That's powerful in the general election, but it's downright crushing in the primaries.

Or, to put it differently, I have heard of Democratic candidates with substantial religious support, but I've never heard of the religious left breaking the back of any candidate's chances. There is no Democratic 700 Club.

-Jester