No.
Next question.
Depends upon what you mean by Christian. If you answer in the affirmative to the question “Can a Methodist or an Episcopalian be Christian?” then, certainly, a Democrat can be a Christian.
Not really. But here is a notable exception.
David Clark, former Milwaukee county sheriff won several terms as a Democrat because he wouldn’t stand a chance there as a Republican. He was a constitutionalist and conservative and the local media hates him with a passion. He was also a big Trump supporter early on.
The answer is no. Same holds to a Republican, American, etc. You either put Christ 1st above all things on earth, or you aren’t squat!