The Senate is learning this week that exercising atrophied constitutional muscles can be hard work — and it comes with political repercussions.

Thursday’s chamber agenda features debate and votes on a joint resolution that would terminate President Donald Trump’s declaration of a national emergency for border security, which is part of his attempt to move money around to build a wall at the border with Mexico. It will be considered under an expedited procedure that will allow for Senate passage without the need for 60 votes to overcome a filibuster.

As of Wednesday evening, that resolution appeared likely to pass the Senate, but fall well short of the two-thirds needed to avert a presidential veto.

Republicans had tried to rally around an effort led by Sen. Mike Lee of Utah that would have amended the National Emergencies Act, going forward, to provide for the automatic termination of future emergencies after 30 days unless Congress acted to authorize them to continue.

But Trump short-circuited that effort when he  informed Lee in a phone call Wednesday that he was against his proposed compromise bill, according to a Republican aide.

Later in the day, Lee issued a statement formally announcing his support for the House-passed joint resolution to terminate the disaster declaration.

“While there was attention on the issue, I had hoped the ARTICLE ONE Act could begin to take that power back. Unfortunately, it appears the bill does not have an immediate path forward, so I will be voting to terminate the latest emergency declaration,” the Utah Republican said. “I hope this legislation will serve as a starting point for future work on this very important issue.”

Before the president weighed in, the Lee-led effort was gaining significant GOP support, including from Texas Sen. John Cornyn.

“Rather than engaging with the president and debating whether the president has the authority to declare a national emergency for border security, which he clearly does, I think our discussion should focus on the structure of emergency powers laws moving forward and whether Congress has delegated too much power not just to this president, but to any president, under these circumstances,” Cornyn said in a statement.

Speaker Nancy Pelosi had made clear, however, that the House had no interest in Lee’s effort.

“Republican Senators are proposing new legislation to allow the President to violate the Constitution just this once in order to give themselves cover,” the California Democrat said in a statement. “The House will not take up this legislation to give President Trump a pass.”

Constitutional conflict

Despite broad support for the border wall among Republicans, they are far from unified on the underlying question of whether the national emergency designation and associated effort to reallocate federal funds is constitutional.

Tennessee Sen. Lamar Alexander, the chairman of the Appropriations Subcommittee on Energy and Water, has for weeks been calling for the Trump administration to take a different approach to finding funding for wall construction that would avoid running into the congressional power of the purse.

“If President Trump can build a wall when Congress has refused to provide the funding, then the next president can declare a national emergency and tear the wall down or declare a climate change emergency and stop oil exports and offshore drilling,” Alexander said last month. “There is no limit to the imagination of what the next left-wing president could do to harm our country with this precedent.”

Still, Republicans including Sen. Thom Tillis of North Carolina (who came out quickly in opposition to the emergency designation) have been facing political pressure to support the president.

Trump told reporters Wednesday that no GOP senator had been “beaten up” by the administration over the national emergency termination resolution, but he said plainly he would veto anything aimed at blocking his national emergency at the southern border.

Yemen resolution

The debate over the power of the purse comes one day after senators delivered a similar brushback of the Trump administration over war powers.

Senators voted, 54-46, Wednesday evening to pull back the U.S. from direct support for the Saudi-led war in Yemen, in a reprise of a vote from December.

Sen. Bernie Sanders, the Vermont independent who caucuses with the Democrats, is leading the effort along with Democratic Sen. Christopher S. Murphy of Connecticut, as well as Lee.

“The United States of America, the most powerful country on earth, should not be led into a regional war by our client states trying to serve their own narrow and selfish interests. Saudi Arabia is a monarchy controlled by one of the wealthiest families in the world,” Sanders said ahead of the vote.

While the Senate went through the same expedited process at the end of the last Congress, the House GOP majority at the time declined to schedule a vote.

The resolution passed the Democrat-led House in a different form this year when members amended the companion resolution at the last minute via a motion to recommit, and it will need another House vote in order to get to Trump’s desk for a veto.

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John T. Bennett contributed to this report.