Yet Mr. McConnell, who strongly advised Mr. Trump against declaring the emergency declaration, made a point of not pressuring senators to support Mr. Trump, urging them to vote according to their consciences and political interests, according to seven Republican aides and lawmakers.
In a volley of phone calls with Senate Republicans over the last few weeks, the president warned of the electoral consequences of defying his will and dismissed concerns about the constitutional precedent of his order.
The president attempted to cajole a handful of members to vote his way during a meeting on trade at the White House on Wednesday afternoon, emphasizing that a vote “against border security” would be noticed by the party’s base, according to two people who attended.
But Mr. Trump also personally sunk attempts by Republican senators this week to limit the number of defections to a handful, an endeavor that would have saved the president a second embarrassing loss in a week that also featured a bipartisan rebuke of his dogged support for Saudi Arabia’s war in Yemen, even after the killing of the dissident journalist Jamal Khashoggi.
When Mr. Paul, a libertarian who frequently bucks his party, announced his support for the resolution, the president flew into a rage, according to two people with knowledge of the situation — and called Mr. Paul to demand that he reverse himself. The senator refused.
And when Mr. Lee proposed an alternative measure — a bill that would restrict future uses of emergency declarations, but leave Mr. Trump’s order in place — and discussed it in a meeting with other undecided senators and Vice President Mike Pence, Mr. Pence expressed support, according to multiple people briefed on the meeting.
The next day, Mr. Trump called the Utah Republican in the middle of a Republican policy lunch to inform him that he did not, in fact, support the measure. Mr. Lee, who announced the president’s verdict to gasps from his colleagues, later declared his support for the resolution.