WASHINGTON (AP) — The Senate is headed toward a vote Wednesday on a war powers resolution that would put a check on President Donald Trump’s ability to carry out further military attacks on Venezuela, but the president was putting intense pressure on his fellow Republicans to vote down the measure.

Trump has lashed out at five GOP senators who joined with Democrats to advance the resolution last week, raising doubts that the measure will ultimately pass. Yet even the possibility that the Republican-controlled Senate would defy Trump on such a high-profile vote revealed the growing alarm on Capitol Hill about the president’s expanding foreign policy ambitions.

Democrats are forcing the vote after U.S. troops captured Venezuelan leader Nicolás Maduro in a surprise nighttime raid earlier this month.

“Here we have one of the most successful attacks ever and they find a way to be against it. It’s pretty amazing. And it’s a shame,” Trump said at a speech in Michigan Tuesday. He also hurled insults at several of the Republicans who advanced the legislation, calling Sen. Rand Paul of Kentucky a “stone cold loser” and Sens. Lisa Murkowski of Alaska and Susan Collins of Maine “disasters.”

Trump’s latest comments followed earlier phone calls with the senators, which they described as terse. The president’s fury underscored how the war powers vote has taken on new political significance as Trump also threatens military action to accomplish his goal of possessing Greenland.

The legislation, even if passed by the Senate, has virtually no chance of becoming law because it would eventually need to be signed by Trump himself. But it represented both a test of GOP loyalty to the president and a marker for how much leeway the Republican-controlled Senate is willing to give Trump to use the military abroad.

Republican leaders move to dismiss the bill

Republican Senate leaders are trying to defuse the conflict between their members and Trump as well as move on quickly to other business. On Wednesday evening, they were moving to dismiss the measure under the argument that it is irrelevant to the current situation in Venezuela. That procedure was subject to a vote.

In a floor speech Wednesday morning, Senate Majority Leader John Thune, R-S.D., vented his frustration as he questioned whether this war powers resolution should be prioritized under the chamber’s rules.

“We have no troops on the ground in Venezuela. We’re not currently conducting military operations there,” he said. “But Democrats are taking up this bill because their anti-Trump hysteria knows no bounds.”

Democratic Sen. Tim Kaine, who has brought a series of war powers resolutions this year, accused Republicans of burying a debate about the merits of an ongoing campaign of attacks and threats against Venezuela.

“If this cause and if this legal basis were so righteous, the administration and its supporters would not be afraid to have this debate before the public and the United States Senate,” he said in a floor speech.

Two Republicans

reconsider

Sen. Josh Hawley, a Missouri Republican who helped advance the war powers resolution last week, has indicated he may change his position.

Hawley said that Trump’s message during a phone call last week was that the legislation “really ties my hands.” The senator said he had a follow-up phone call with Secretary of State Marco Rubio that was “really positive.”

Hawley said that Rubio told him Monday “point blank, we’re not going to do ground troops.” The senator said he also received assurances that the Trump administration will follow constitutional requirements if it becomes necessary to deploy troops again to the South American country.

“We’re getting along very well with Venezuela,” Trump told reporters at a ceremony for the signing of an unrelated bill Wednesday.

Hawley’s position left the vote margin for the resolution, which advanced 52-47 last week, razor thin.

However, Collins told reporters Wednesday she will still support the resolution. Murkowski and Paul have also indicated they won’t switch.

That left Sen. Todd Young, an Indiana Republican, with the crucial vote. He declined repeatedly to discuss his position but said as he headed to the Senate floor that he had been given “incredible access to our senior national security leaders.”

What is the war

powers resolution?

Under the Constitution, Congress alone has the ability to declare war. But U.S. presidents have long stretched their powers to use the might of the U.S. military around the globe.

Ohio State University professor Peter Mansoor, a military historian and retired U.S. Army colonel with multiple combat tours, said that trend since World War II allows Congress to shirk responsibility for war and put all the risk on the president.

In the post-Vietnam War era, lawmakers tried to take back some of their authority over wartime powers with the War Powers Resolution of 1973. It allows lawmakers to hold votes on resolutions to restrict a president from using military force in specific conflicts without congressional approval.

“Politicians tend to like to evade responsibility for anything — but then this gets you into forever wars,” Mansoor said.