Here is a direct quote from the U.S. Constitution: “No religious test shall ever be required as a qualification to any office or public trust under the United States.”
Note that the restriction is on government and not on individuals. Every citizen can apply whatever reason they choose in deciding who gets their vote—including the use of religious beliefs to make a political decision. But nobody can be disqualifed from public office because of their faith, or their lack of it.
Throughout American history, candidates have tried to make an issue out of the religion of a political opponent. The practice has a checkered history. That’s partly because of the backlash against religious attacks. Such attacks often fail because most Americans cherish that important liberty stated in the Bill of Rights, in the very first amendment, namely freedom of religion. That’s the American way.
From The Heritage Foundation, I’m Ernest Istook.