WASHINGTON — Sen. Rand Paul, R-Ky., appeared to signal support this weekend for a resolution that would overturn President Donald Trump’s declaration of a national emergency at the southern border, which would provide the crucial vote needed for the Senate to pass the measure.

“I can’t vote to give the president the power to spend money that hasn’t been appropriated by Congress,” said Paul, speaking Saturday at the Southern Kentucky Lincoln Day Dinner, according to The Bowling Green Daily News. “We may want more money for border security, but Congress didn’t authorize it. If we take away those checks and balances, it’s a dangerous thing.”

Paul did not explicitly say whether his opposition to giving “extra-constitutional powers to the president” would lead him to vote for the measure. But his remarks offered the clearest indication that he would join three other Republican senators — Susan Collins of Maine, Thom Tillis of North Carolina and Lisa Murkowski of Alaska — in backing the resolution. His support would provide the slim majority Democrats need to send the measure to the president’s desk, offering a stinging repudiation of the declaration.

David Graham, chairman of the Warren County Republican Party, which hosted the event, confirmed Paul’s remarks. A spokesman for Paul did not respond to requests for comment.

The House, largely on party lines, passed the resolution Tuesday, and under the National Emergencies Act of 1976, the Senate is required to vote on the resolution in the coming weeks. Trump has said he would veto the measure, and it is unlikely that either chamber could muster the two-thirds majority needed to override a veto.

But with several lawsuits already filed, a resolution of disapproval from Congress — the simplest mechanism for lawmakers to challenge a declaration — could help opponents of the declaration.

The comments from Paul, a libertarian who frequently rails against government spending and often has no qualms about bucking his party, underscore the unease among Senate Republicans about the president’s attempt to divert funds without congressional approval.

But with time before the Senate has to vote, Trump and his allies have an opportunity to lobby Paul. Such tactics have been successful before: The Senate Foreign Relations Committee was poised to give Mike Pompeo’s nomination as secretary of state an unfavorable recommendation until Paul bowed to pressure and gave his approval.

Trump, who was repeatedly denied wall funding by lawmakers, hopes to use $3.6 billion from military construction projects to fulfill his campaign promise to build a wall along the border with Mexico. He has dismissed concerns about the precedent, saying in a speech Saturday that “they’re going to do that anyway, folks.”

Some Republican senators — including James M. Inhofe of Oklahoma, chairman of the Armed Services Committee — have voiced concerns about the effect on military readiness, seeking assurances that projects in their states will not be affected. The Defense Department has yet to release a list of projects affected.

Others, including Paul, have objected to a possible overreach of executive power that future presidents could take advantage of. But few have been willing to publicly say how they will vote on the resolution.

Sen. Lamar Alexander, R-Tenn., said it was “unnecessary and unwise to turn a border crisis into a constitutional crisis about the separation of powers” in a floor speech Thursday, where he outlined other means for obtaining funds.

“There is no limit to the imagination of what the next left-wing president could do to harm our country with this precedent,” he added. But pressed by reporters, he declined to reveal his planned vote.

“I learned a long time ago in the United States Senate, it’s not wise to announce how you will vote on a vote you may never have to take,” he said.

Conversely, Collins joined Sen. Tom Udall, D-N.M., in introducing a resolution of disapproval Thursday. Murkowski joined the pair in co-sponsoring the resolution.

“I think it is very important that Congress stand up for its constitutional authority and that the Senate guard its institutional prerogatives,” Collins told reporters.

This article originally appeared in The New York Times.