The hard fact of constitutional law, though, is that only the senators can control their own behavior. They can act out of religious bias, or other bigotry, and there’s little that can be done about it.
Senators, law professor Paul Horwitz told The Washington Post, are “free to vote against a nominee for religious reasons, just as he or she is free to do so for other reasons, including racism or sexism.”
Senators may violate the spirit of the Constitution, and even the letter, but they can’t be impeached. No matter what they say in any hearing, they can’t be tried for it — or even subpoenaed — in court.