hmm i dont think atheism has anything to be left at home as it is merely a lack of beleif in the supernatural, the only thing it truly promotes is only accepting things based on evidence and probability, which isnt a bad thing for any politician, when politicians go against the evidence because they beleive its for a greater good, any good that comes out of it is usually outweighed by the bad

Also whichever religious beleif the politicion choose to let influence them theres going to be another religion that it offends, by taking all religion out of the picture, it keeps at least some peace between them, at least politcally.