Even if someone was privately an atheist, i find it unlikely that they'd be open about it if running for the office. Everyone seems to end their speeches with "god bless america"

@firstuserhere For the purposes of this market, I need to be confident that they're actually an atheist. They don't need to be super public about it, but it can't just be a "IDK, I respect all religious beliefs" hedge.

https://en.wikipedia.org/wiki/Atheism_in_the_United_States#Public_officials

Oof, 53% of people in 2014 would be less likely to vote for an atheist president, and only 5% more likely.

https://www.pewresearch.org/politics/2014/05/19/for-2016-hopefuls-washington-experience-could-do-more-harm-than-good/