‘Why is it that so many of us on this side have this very uncomfortable feeling that—you know, dogma and law are two different things. And I think whatever a religion is, it has its own dogma. The law is totally different. And I think in your case, professor, when you read your speeches, the conclusion one draws is that the dogma lives loudly within you, and that’s of concern when you come to big issues that large numbers of people have fought for years in this country.”

Thus did California Sen. Dianne Feinstein pronounce on Wednesday that, by virtue of being a faithful Catholic, Amy Barrett, a respected law professor at Notre Dame, may have excluded herself from a federal judgeship. President Trump has nominated Ms. Barrett for the Seventh Circuit Court of Appeals. But the Democratic obsession with Ms. Barrett’s religion transformed what should have been a routine Senate confirmation hearing into a tour of the mind of the modern secular left.

The ugly implication of Mrs. Feinstein’s words is underscored by the context. She deployed them to suggest Ms. Barrett’s faith would lead her to substitute her personal beliefs for the law, basing the accusation primarily on a law review article Ms. Barrett wrote in 1998 as a law clerk.

Ms. Barrett and her co-author explicitly reached the opposite conclusion: “Judges cannot—nor should they try to—align our legal system with the Church’s moral teaching whenever the two diverge.”

The question addressed by the law review article was what Catholic judges ought to do when they conclude they cannot in good conscience apply the law as written because it clashes with their own moral views. If she was rattled by the question, Sen. Feinstein ought to have been reassured by the answer Ms. Barrett gave: They should recuse themselves.