Nothing threatens the progressive project more than the existence of a Supreme Court that adheres to the Constitution. It’s really that simple.

That’s what the tantrum over Justice Amy Coney Barrett’s confirmation is all about. The notion that the same Democrats who shelved the judicial filibuster and now threaten to destroy the separation of powers with a Court-packing revenge scheme — the same people, incidentally, so fond of smear-drenched confirmation hearings — are sticklers for process or decorum is simply ludicrous.

For one thing, no norms have been undone by...