More practically, they required a supermajority for conviction and removal, two-thirds of the Senate. This would mean that no president could be stripped of power absent misconduct so abominable that a public consensus for removal would form, such that two-thirds of senators would be moved to transcend ties of party, ideology and loyalty.

This supermajority requirement was to have a sobering effect on the House, too. Unless presidential malfeasance was sufficiently serious that there was a reasonable chance the Senate would vote to remove, the House would be dissuaded from impeaching in the first place. Members of Congress could expect to be punished at the ballot box for needlessly putting the country through a futile impeachment.

That’s gone now. There is a new kind of politics in America, one we will come to regret. The theory is that elections are won not by broadening a coalition, reaching out to attract or convincing opponents and undecideds. No, they are won by stoking grievance on one’s own side and electrifying one’s base — which is never more united and enthusiastic than when it opposes a political enemy.