A group of Senate Republicans led by Lamar Alexander have given President Donald Trump an ultimatum: Withdraw the border wall emergency declaration or face a rebellion from within his own party.

RAND PAUL: “I don’t think emergencies are a good way to run the government. And the president needs permission from Congress to get money,”

Alexander, R-Tenn., gave a much-anticipated speech on the Senate floor where said there is broad opposition to the emergency declaration, and he sought to convince Trump to find other ways to get the $5.7 billion needed for the wall. The retiring Alexander declined to say whether he will become the deciding vote to block the emergency declaration.

Per Politico:

“He’s got sufficient funding without a national emergency, he can build a wall and avoid a dangerous precedent,” Alexander told reporters afterward, referring to billions from a drug forfeiture fund and anti-drug smuggling money at the Defense Department. “That would change the voting situation if he we were to agree to do that.”

Three Republicans, Sens. Susan Collins of Maine, Lisa Murkowski of Alaska and Thom Tillis of North Carolina, already are on record against the declaration, and the Democrats need just four GOP Senators to block the president with 51 Senate votes. The Democrat-controlled House voted 245-182 to block the declaration on Tuesday. The House vote included 13 Republicans who sided with the Democrats.

Alexander is reportedly one of about 10 Republican senators who are committed to blocking the emergency declaration, or are at least considering it, according to Politico.

The president has already threatened to veto a Congressional block, which would force another vote in both chambers that would require a two-thirds majority to then override the veto.

Asked how the GOP can avoid a battle with Trump, one Senate Republican considering voting for the disapproval resolution said: “He can change his mind.”

“The president can get way more money than he’s even asking for without setting the Constitution on its head,” said this undecided senator, who requested anonymity to speak frankly. “I am very, very skeptical about the precedent this makes.”

In 2005, President George W. Bush withdrew an emergency plan for paying disaster workers after Congress threatened to block him.

If Trump doesn’t back down, there is still deep reluctance in the GOP to becoming the 51st vote for the disapproval resolution that the Senate is expected to vote on in March.

The president told Sean Hannity that Republicans who oppose him “put themselves at great jeopardy” and said it’s “very dangerous” to vote against border security. Some GOP senators shrugged off that sentiment.

“I always do what I think is the right thing to do,” said Sen. Johnny Isakson (R-Ga.), who is undecided. “As long as I’m satisfied with myself, that’s the person I’m going to satisfy.”

Republicans spent all week debating how to deal with the political headache of seeing a president from their party use some of the same unilateral tactics they panned under President Barack Obama.

After introducing her own resolution of disapproval directly on the Senate floor Thursday, Collins said her “Republican colleagues are very uneasy about the precedent.”

“I don’t think emergencies are a good way to run the government. And the president needs permission from Congress to get money,” said Sen. Rand Paul (R-Ky.) on Thursday. Despite those words, he hasn’t made a “final decision” on his vote.

“I have long believed and advocated that every president, Republican and Democrat, should act consistent with the Constitution and federal law. And I’m assessing those legal authorities right now,” said Sen. Ted Cruz (R-Texas).

GOP senators are discussing amending the House-passed disapproval resolution to make it more palatable to both them and Trump, but say they are not sure it will be allowed by the Senate parliamentarian. The resolution has been referred to the Senate Armed Services Committee, but Chairman Jim Inhofe (R-Okla.) said his committee will hold no hearings on it.

“There’s some discussion about: Is there a way to give the president what he asks for in terms of funding but to minimize the use of this mechanism in the future?” said Sen. John Cornyn (R-Texas), who will oppose the resolution as written.

Despite his clear opposition to Trump’s national emergency declaration, Alexander deemed the looming vote on disapproval a hypothetical, since Trump could withdraw it or the House-passed resolution could be amended. Under current law, the House measure will come up by mid-March, and Alexander left little doubt that he’s just one of a large bloc of Republicans who could defy the president.

Trump’s national emergency declaration for border wall funding is “unnecessary, unwise and inconsistent with the Constitution,” Alexander told reporters. “And many Republican senators who can speak for themselves share that view.”

“We’ve never had a case where the president has asked for money, been refused the money by Congress, then used the national emergency powers to spend it anyway,” he added. “To me that’s a dangerous precedent.”