The bill had been approved by Democrats and five Republicans who broke party lines last week.
Donald Trump has since put heavy pressure on the five Republicans to change their minds, and in Wednesday's vote to reject the bill, two of them did just that.
The vote was thus tied 50–50, and Vice President J.D. Vance had the casting vote.
Even if the bill passed the Senate, it was unlikely to actually become law as Trump himself would have had to sign it. The vote is seen by many as a way for the Senate to express displeasure with Trump's attack on Venezuela - which he carried out without informing or consulting Congress.
