The Senate voted 59-41 to block President Donald Trump's border-emergency declaration.

A dozen Republicans joined all 47 Democrats to pass a resolution of disapproval of the declaration. The 12 GOP senators were: Lamar Alexander (Tenn.), Roy Blunt (Mo.), Susan Collins (Maine), Mike Lee (Utah), Jerry Moran (Kan.), Lisa Murkowski (Alaska), Rand Paul (Ky.), Rob Portman (Ohio), Mitt Romney (Utah), Marco Rubio (Fla.), Pat Toomey (Pa.), and Roger Wicker (Miss.)

What happened?

On Feb. 15, following a protracted spending battle that led to a record-long partial government shutdown, Trump declared a national emergency on the southern border. His move came after he signed a compromise spending bill to keep the government open for the remainder of the fiscal year.

The spending measure included only $1.375 billion for 55 miles of border fence in a limited region. The president had been seeking $5.7 billion. The fight over border wall funding was the sticking point that led to the government shutdown.

Trump's emergency declaration would allow the president to redirect billions of dollars from other areas to fund the border wall. Most of the redirected funds would come from the Department of Defense.

In response to Trump's emergency declaration, the Democratic-controlled House passed last month a resolution to block the president's move. Thirteen Republicans joined the entire Democratic caucus to approve the measure, 245-182.

Republican backers of the resolution have repeatedly stated that their opposition to Trump's emergency declaration is not based on opposition to building the border wall but on the president's plan to spend money that Congress did not allocate. Article 1 of the Constitution gives Congress sole power of purse.

Conservative critics of Trump's declaration have also warned that if this emergency is permitted to stand — despite the seemingly non-emergency nature of wall-building, which will take years to complete — then future Democratic presidents could abuse emergency powers to enact their priorities.

President Trump himself said on the day he signed the emergency declaration, "I could do the wall over a longer period of time, I didn't need to do this, but I'd rather do it much faster."

Florida Republican Sen. Marco Rubio warned:



We have a crisis at our southern border, but no crisis justifies violating the Constitution. Today's national emergency is border security. But a future president may use this exact same tactic to impose the Green New Deal. I will wait to see what statutory or constitutional power the President relies on to justify such a declaration before making any definitive statement. But I am skeptical it will be something I can support.

The National Emergencies Act, which allows Congress to stop a presidential emergency declaration, requires that, after House passage, the Senate must bring up the House-passed resolution of disapproval. The resolution is privileged and, therefore, cannot be filibustered.

With 47 Democrats in the Senate, the minority party needed only four Republicans to join them to pass the resolution. On March 4, Kentucky Sen. Rand Paul announced he would be the fourth Republican vote — joining Sens. Susan Collins, Lisa Murkowski, and Thom Tillis.

Tillis declared shortly before the vote Thursday that he had changed his mind and would vote against the resolution. His flip-flop came following reports of pressure from the White House.

The number of GOP senators who jumped ship and joined the Democrats grew after President Trump shot down a proposal led by Utah Sen. Mike Lee — and backed by 14 other Republicans — to rein in presidential power to declare emergencies.

Lee's bill would have had no impact on Trump's border emergency declaration. The bill would have amended the National Emergencies Act to give Congress 30 days to extend a presidential emergency declaration. If Congress chose not to extend it, the declaration would automatically end.

Lee said he offered the bill as a deal to President Trump in exchange for support for his emergency declaration. The Utah senator revealed Wednesday that "the president didn't appear interested," so he would be voting in favor of the disapproval resolution.

Sen. Mitt Romney joined his fellow Utah Republican Thursday, declaring that he would also vote to block Trump's emergency declaration. He said in a news release:

I will vote today for the resolution of disapproval. This is a vote for the Constitution and for the balance of powers that is at its core. For the Executive Branch to override a law passed by Congress would make it the ultimate power rather than a balancing power.



This is not a vote against border security. In fact, I agree that a physical barrier is urgently needed to help ease the humanitarian crisis at the southern border, and the administration already has $4.5 billion available within existing authority to fund a barrier – even without an emergency declaration.



I am seriously concerned that overreach by the Executive Branch is an invitation to further expansion and abuse by future presidents. We experienced a similar erosion of congressional authority with President Obama's unilateral immigration orders – which I strenuously opposed. In the case before us now, where Congress has enacted specific policy, to consent to an emergency declaration would be both inconsistent with my beliefs and contrary to my oath to defend the Constitution.

According to a Thursday report from CNN's Kaitlin Collins, GOP Sens. Lindsey Graham (S.C.), Ted Cruz (Texas), and Ben Sasse (Neb.) tried to visit the White House Wednesday afternoon to discuss the Lee bill but were turned away. Graham returned to the White House that night and "barged" in to tell the president "there would be fewer GOP defection" on the disapproval resolution if he would support the Lee proposal. But Trump refused.

President Trump took to Twitter Thursday morning to both again defend his emergency declaration and to state that he is open to future changes to the National Emergencies Act.

"Prominent legal scholars agree that our actions to address the National Emergency at the Southern Border and to protect the American people are both CONSTITUTIONAL and EXPRESSLY authorized by Congress," Trump tweeted. "If, at a later date, Congress wants to update the law, I will support those efforts, but today's issue is BORDER SECURITY and Crime!!! Don't vote with Pelosi!"

Also on Thursday morning, hours before the Senate vote, Trump blasted any Republicans who would choose to support the disapproval resolution, saying, "A vote for today's resolution by Republican Senators is a vote for Nancy Pelosi, Crime, and the Open Border Democrats!"



What happens next?



The resolution now heads to the president's desk. Trump has made it clear that he will veto the resolution.

He reiterated his intention to veto the resolution in a statement Thursday on Twitter: "A big National Emergency vote today by The United States Senate on Border Security & the Wall (which is already under major construction). I am prepared to veto, if necessary. The Southern Border is a National Security and Humanitarian Nightmare, but it can be easily fixed!"

Congress has the option to vote to override the veto, but that move requires a two-thirds majority in both houses. The resolution did not receive support from two-thirds of the members in either chamber.



Next up, the emergency declaration faces multiple court challenges from opposition groups and at least 16 states, with California leading the charge.

The White House has repeatedly stated that it will defend the emergency declaration.