Contrary to Dr. Ben Carson's claim that a Muslim cannot be President of the United States, article 6, section 3 of the U.S. Constitution states that "no religious test shall ever be required as a Qualification to any office or public trust under the United States."
The First Amendment declares that "Congress shall make no law respecting an establishment of religion or prohibiting the free exercise thereof."
As George Washington stated in 1790 in his letter to the Jewish community of Newport Rhode Island, the government of the United States "requires only that those who live under its protection should demean themselves as good citizens."
The Treaty with Tripoli, negotiated under George Washington and John Adams, stated that the United States was not based on the Christian religion and would have no reason for hostility towards Muslims.
The lack of any mention of God or Christianity in the Constitution was complained of by Christians during the debates over ratification but the Constitution was ratified anyway, showing that the founders knew what they were doing.
Because of presidential candidates like Donald Trump, I suppose it should not be too surprising that candidates for President should be so ignorant of the provisions of the Constitution or the founding principles of this country. What is truly mind boggling however is that Ben Carson, who managed not only to graduate from high school but also college and continue on to obtain an M.D. degree should be so ignorant about this country's founding document. I learned about the Treaty with Tripoli and the U.S. not being based on the Christian religion in my American history course when I was a Junior in high school!