Yet what Republicans have learned after nearly 30 months with Trump in the White House is that the president can turn on a dime. The Mexico tariff threat was a perfect example: Trump’s tweet announcing the move to impose new tariffs without new immigration controls jolted nearly everyone in the Capitol and thrust Washington into a week of drama, even if some Democrats said they always thought Trump was bluffing.

“He made a bogus threat to impose tariffs, which the business community and Republicans in Congress rejected,” Senate Minority Leader Chuck Schumer said. “And now the president claims a bogus agreement with Mexico which contains policies that Mexico volunteered to do months ago. Bogus, bogus, bogus.”

Yet Trump also experienced unprecedented Republican pushback: The party has not yet before offered to provide a veto-proof majority in opposition to his policies, a real escalation of the intraparty feud. But Trump seems unbowed, even threatening new tariffs on French wine on Monday…

[T]he blowback could only increase the next time the president brings them up. For one, any more significant delay could imperil the USMCA deal altogether. Pelosi is reluctant to bring it up in the first place, and Republican leaders have said that after the August recess the chance of approval decreases exponentially.