WASHINGTON — The GOP-run Senate on Thursday voted 59-41 to pass a resolution of disapproval against President Donald Trump’s national emergency at the U.S.-Mexico line, providing an unprecedented rebuke of the White House's contentious move to build a border wall.

Neither Texas Sens. Ted Cruz nor John Cornyn joined in bucking the commander in chief.

While Cornyn last month already made clear he would vote against the House-passed measure authored by Rep. Joaquin Castro, D-San Antonio, Cruz had allowed anticipation to build for days by being coy about how he would handle Trump's executive end-run.

Cruz, an avowed constitutional conservative, has a long and vocal history of criticizing presidential overreach, particularly during the tenure of President Barack Obama.

But Cruz ended up backing Trump, yet again underscoring his rock-solid support for the president. He announced his choice with a simple thumbs-down on the Senate floor — later saying that Trump was acting within his authority — even as a dozen other Republican senators defected.

"Today's question was whether there was an emergency at our southern border," he said in a news release, while still expressing concern about potential abuse of national emergency declarations to circumvent Congress. "There is, and I voted to recognize that tragic fact."

The action on Thursday will likely have little bearing on the national emergency’s ultimate fate, which is now all but assured to be decided by the courts.

Enough Republican senators had announced their support for the resolution to block Trump's emergency ahead of the vote to assure passage. Not nearly enough Republican senators, as expected, ended up doing so for it to survive the veto that Trump has said is “100 percent” going to happen.

Sen. Ted Cruz, R-Texas, prepared to leave a hearing in the Dirksen Senate Office Building on Capitol Hill this week in Washington. (Chip Somodevilla / Getty Images)

Cruz's choice still provided an intriguing marker in the complicated relationship between him and Trump, particularly since the president had taken to Twitter to tell the Senate GOP to “get tough.”

“Republican Senators are overthinking tomorrow’s vote on National Emergency,” he wrote on Wednesday. “It is very simply Border Security/No Crime — Should not be thought of any other way. We have a MAJOR NATIONAL EMERGENCY at our Border.”

Cruz, who clashed with Trump during the 2016 White House race, had earlier been part of a group of GOP senators seeking a compromise that would allow them to avoid a direct rebuke of Trump while also taking some action to limit executive power.

A vote for today’s resolution by Republican Senators is a vote for Nancy Pelosi, Crime, and the Open Border Democrats! — Donald J. Trump (@realDonaldTrump) March 14, 2019

The proposal authored by Utah Sen. Mike Lee — and co-sponsored by Cruz, Cornyn and a host of other GOP senators — would have caused an emergency declaration to automatically expire after 30 days unless both the House and the Senate voted to keep it.

But Trump equivocated on that approach. House Speaker Nancy Pelosi, even before Trump weighed in, declared the idea a no-go in her Democrat-run chamber. And in any case, Democrats in Texas and beyond put the laser focus on the disapproval resolution itself.

"Fifty-nine senators stood up to the president today and stood up for the Constitution," Castro said. "Unfortunately in Texas, that did not include either of our senators ... who showed weakness today, who showed timidity, who betrayed the people of Texas in favor of Donald Trump."

Rep. Joaquin Castro, D-San Antonio, authored the resolution of disapproval. He said he was asking the "Senate to take a stand for the Constitution." (Photo by Chip Somodevilla/Getty Images) (Chip Somodevilla / Getty Images)

Trump invoked the national security declaration after a titanic clash with Democrats, who took control of the House this year for the first time since 2011.

The president had started by demanding $5.7 billion for his wall along the U.S.-Mexico border. Democrats and a handful of Republicans said no. Trump then followed through on his pledge to shut down the federal government over the matter, leading to a record-setting stalemate.

Congressional negotiators appeared to resolve the impasse in February by agreeing to give Trump $1.4 billion for border fencing.

But the president, while accepting that funding, deemed the amount unsatisfactory. He declared the national emergency to bypass Congress and reprogram money toward a border wall from accounts marked for military construction and other priorities.

Trump’s efforts would siphon off about $6.6 billion for his wall, which he says is pivotal in boosting security along the U.S.-Mexico line.

Democrats — already dismissive of the wall as a needless folly — pounced on Trump’s move. Castro authored the measure to block Trump's declaration, with he and others raising concerns about separation of powers, the potential hit to the military and a negative impact to border residents.

“This land grab is massive,” Rep. Vicente Gonzalez, D-McAllen said. “It’s un-American. It’s un-Texan. It seems to ignore the real issues that we’re dealing with on the border.”

Adding to Democrats’ gall was that Trump just this week asked for an additional $8.6 billion for border wall funding in his 2020 budget request.

“President Trump’s request is simply short-sighted and fiscally irresponsible,” said Laredo Rep. Henry Cuellar, a Democrat on the House Appropriations Committee. “Any budget that allocates billions towards a border wall is bad policy and an unacceptable waste of taxpayer dollars.”

Rep. Henry Cuellar, D-Laredo, criticized not just Trump's national emergency, but also the president's request for even more money toward a border wall. "Any budget that allocates billions towards a border wall is bad policy and an unacceptable waste of taxpayer dollars," he said. (Todd J. Gillman / Dallas Morning News)

House vote

The official rebuke last month passed the House with ease.

But just 13 Republicans joined every Democrat in supporting the measure. The only Texas Republican in the bunch was San Antonio Rep. Will Hurd, a border barrier critic who ripped the idea that military construction funds would go toward Trump’s wall.

That tally meant the House was not even close to the two-thirds majority needed to survive a Trump veto.

Republicans in the Senate, then, had a choice. They could stand up to Trump after the president ignored their loud pleas for him to not pursue the national emergency route. But that would also mean risking Trump’s wrath over a measure that was not going to succeed anyway.

While Cruz took his time coming to a decision — even amid his staunch support for Trump’s border wall — some in the GOP moved quickly to back the president.

Cornyn's concern

Take Cornyn, who’s up for re-election next year. He said Trump’s move was “obviously no one’s first choice,” that he was concerned about setting a bad precedent and that it wasn’t the “best way for Congress and the White House to deal with situations like this.”

He nevertheless decided to vote against the resolution of disapproval.

“To those who would somehow argue that this is a fake emergency or not a serious situation, I disagree,” Cornyn said on Wednesday. “I will continue to support efforts to bring security to the border.”

Cruz echoed that point.

"Make no mistake: an emergency absolutely exists on the border, and it is a national and humanitarian disaster," he said, stressing the need to build a wall.

The senators who supported Trump's effort had backup from other Republicans outside of D.C.; Texas Attorney General Ken Paxton, for instance, co-authored a piece in USA Today defending Trump's declaration. But there was also pressure for Republicans to buck Trump.

A group called Republicans for the Rule of Law ran an ad on Fox News that showed clips of Cruz denouncing Obama for acting like an "unaccountable monarch” and of Cornyn accusing Obama of "abusing executive authority."

"If Republicans were against executive overreach then, they should be against it now," the ad said.

The 12 Republican senators to vote for the disapproval resolution were Sens. Lamar Alexander of Tennessee, Roy Blount of Missouri, Susan Collins of Maine, Mike Lee of Utah, Jerry Moran of Kansas, Lisa Murkowski of Alaska, Rand Paul of Kentucky, Rob Portman of Ohio, Mitt Romney of Utah, Marco Rubio of Florida, Pat Toomey of Pennsylvania and Roger Wicker of Mississippi.