In a back-and-forth with me via email, Luttig wrote, “This constitutional moment is, in principle, for the Article II Executive, what it would be, in principle, for the Article I Legislature, were the President himself to draft legislation declaring war on behalf of the United States, purport to enact it and sign it into law, and immediately thereafter commit the United States to war through the launch of inter-continental ballistic warheads.”

“As it would be, in same principle,” Luttig continued, “the constitutional moment for the Article III Judiciary were the Congress of the United States to have purported in legislative session to decide this very case that had been pending before the Supreme Court and, before the Supreme Court decided the case yesterday, forbad the President through congressional enactment from asking persons living in the United States whether they were or were not lawful citizens of the United States of America.”

So it is not merely “a single question on the 2020 census” decision. It is the question: To which branch does the Constitution commit which powers? Get that wrong, and the walls of separation are down, the checks don’t balance. It’s open season, one branch upon the other.