If a candidate's theology were to be the deciding factor, I'd just stop voting.
There will never be a Coptic Orthodox president/head of state. Good thing we realized that over 1700 years ago. Better to be in the desert than in the White House anyway.
Failing that, I try to vote for whoever seems least likely to believe that the rest of the world works like the USA does/that everyone thinks like an American political hack.
Because of this, I have not really had anyone good to vote for in my life. I doubt that's ever going to change.
Of course I wouldn't vote for a Muslim, but that has less to do with my objections to Islamic theology specifically than it does my objections to the Islamic synthesis of religion and politics that does not allow for the proper development of a pluralistic civil society. If we're all going to share one country, the leader, other government functionaries, and the constitution they operate under can't apportion rights based on the citizenry's membership in a given religion or sect, which is the entirety of what the Islamic concept of rights has always been based around, going back to the Constitution of Medina which the Muslims say was authored by Muhammad himself (read: you do not have rights because you are a person of the governed territory, but only because/if you are a member of a religious community that Islamic law recognizes; this is why even today in places like Egypt groups like Baha'is and atheists may be barred from attending school, marrying, etc.; the dominant religion which controls the culture and sets policy encourages this behavior, in addition to the terrible treatment of people of the other religions it does recognize, which in an Egyptian legal context are Judaism and Christianity.)
