U.S. Senate Republicans blocked a resolution on Wednesday that would have barred President Donald Trump from further military action in Venezuela without Congress’ authorization, after the Republican president put pressure on party members who had supported it.

The vote was 51-50 for a Republican point of order to dismiss the war powers resolution, as just three of Trump’s Republicans voted with every Democrat in favor of moving ahead and Vice President JD Vance came to the Capitol to break the tie.

Opponents had argued that the resolution should not move ahead because the U.S. does not currently have troops on the ground in Venezuela, after U.S. forces swept into Caracas on January 3 and captured Venezuelan President Nicolas Maduro.

“We’re not currently conducting military operations there,” Republican Senate Majority Leader John Thune of South Dakota said, as he opened the Senate on Wednesday. “Democrats are taking up this bill because their anti-Trump hysteria knows no bounds.”

The Trump administration argues that Maduro’s capture was a judicial operation to bring him to trial in the U.S. on drug charges, not a military operation.

Backers of the war powers resolution disagreed, noting that a large flotilla of U.S. ships is blockading Venezuela, and has spent months firing on boats in the southern Caribbean and Pacific. Trump also has threatened further military action.

“An argument that the Venezuela campaign is not imminent hostilities within the meaning of the war powers resolution is a violation of every reasonable meaning of that term,” Democratic Senator Tim Kaine of Virginia, a lead sponsor of the resolution, said in a speech before the vote.

The close votes reflected concern in Congress, including from some Republicans, about Trump’s foreign policy and growing support for the argument that Congress, not the president, should have the power to send U.S. troops to war, as spelled out in the U.S. Constitution.

Trump recently has said the U.S. will run Venezuela for years, told Iranians protesting against their government that “help is on the way” and threatened military action to take Greenland, a territory of NATO ally Denmark.