A handful of Republicans joined Democrats to allow the measure to move forward, reflecting concerns in both parties about the administration’s strategy.
“Make no mistake: Bombing another nation’s capital and removing their president is an act of war, plain and simple,” Senator Rand Paul, Republican of Kentucky, said before the vote.
The Republican defectors paved the way for a debate that could expose bipartisan concern about President Trump’s actions in Venezuela. Mr. Trump called for them to lose their seats.