Mrs. May has delayed a parliamentary vote on her compromise deal, acknowledging that it would have faced defeat “by a significant margin.” Parliament is to hold an emergency debate today on the postponement of the vote, and a spokesman for Mrs. May said lawmakers would get a chance to vote on the deal some time before Jan. 21.

What’s at stake: Without an agreement, Britain would face a so-called cliff-edge Brexit, with banking, trade, travel and rules at the border between Ireland and Northern Ireland potentially changing overnight on March 29. But that’s not the only way things could go. We sketch out the possible scenarios, including a second Brexit referendum.

The Daily: On today’s episode, our correspondents in London discuss frustrations in Britain.

From Opinion: A writer for The Spectator, a British weekly magazine, has a request: “Pray for us.”

President Trump lays out a defense

Mr. Trump said on Monday that payments made to two women for their silence about alleged extramarital affairs with him were “a simple private transaction” and were not subject to campaign-finance laws.