Catholics believe in free will
Mormons believe in free will
Muslims do not. They preach tyranny.
Should a communist be president? They believe in tyranny.
This is not about a religion, this is about political beliefs.
Islam is a religion and politics wrapped up in one. They believe in a tyrannical theocracy.
Ben is right.
Personally, I don’t think Communists, Atheists, Moslems, Cthulhu Cultists, Ba’al or Moloch worshippers, or worshippers of Aztec gods should be President, but I would never present the argument against them in that fashion.
There is an article in the Constitution that prevents the government from considering the religion of a candidate, and there is the First Amendment which protects Freedom of Religion.
I would limit my arguments to the candidates platform and to any personal issues he might have that make him less suitable.