Dominic Cummings, the prime minister’s chief aide and the architect of the successful Leave campaign in the 2016 referendum, is said to be urging Mr. Johnson to defy the new law by refusing to ask Brussels for a delay, ministers say. That could trigger a clash with courts.

Regardless of what happens in Parliament, British voters have united on one front: They have lost faith in their politicians. “They’re all idiots,” said one voter. “Stuck up, stupid, useless idiots.”

Reminder: At the end of this week, Parliament will break for party conferences and won’t return until Oct. 14.

Analysis: When rebel Conservative lawmakers staged a dramatic revolt against Mr. Johnson last week, dispirited Republicans across the Atlantic saw a lesson in how a center-right party can stand up to a wayward leader.