His support for enhanced border security means he can’t be dismissed by Trump as just another Democrat who supposedly favors open borders. Unfortunately, thus far Romney has reacted only tepidly, putting out a statement saying: “I will reserve judgment on any potential executive action by the President until I am able to fully evaluate it, but as I’ve said, I do not believe declaring a national emergency is the right approach. I would also expect the President to stay within statutory and constitutional limits.”

At a moment of choosing for the republic, this whispered criticism will not do. If Romney were to issue a full-throated denunciation of the emergency proclamation from the high ground he occupies, he could make all the difference. Win or lose the fight, if he were to rise in the Senate to explain the stakes for the American project of limited government and forcefully speak out for the rule of law, he would secure an honored place in our history as a defender of the constitutional order at a moment when it is under grievous threat.