WASHINGTON – The House voted 245-182 Tuesday to block President Donald Trump's declaration of a national emergency along the southern border, but Democrats didn’t win enough support from Republicans to overcome Trump’s threatened veto.

Only 13 Republicans joined all Democrats in backing the measure, even though many had warned against the declaration.

GOP Rep. Cathy McMorris Rodgers of Washington said she was “100 percent in favor of President Trump’s wall" but Congress shouldn't give up its power delegated by the Constitution.

"When that power is delegated to the executive or judicial branches, representatives become elected bystanders and ‘We the People’ no longer have a voice," McMorris Rodgers said.

The GOP-controlled Senate must weigh in on the "privileged resolution" within 18 days.

Vice President Mike Pence and legal experts discussed the emergency declaration with Republican senators during their weekly caucus lunch Tuesday. Several senators said afterward they were still processing the information.

“One thing that’s not in debate in our conference – we really do think there’s a crisis at the border,” said Majority Leader Mitch McConnell of Kentucky. “There are different points of view about how to address that.”

Trump declared an emergency this month after Congress sent to the president a bipartisan funding bill that failed to meet his demand for $5.7 billion for a wall along the U.S.-Mexico border. Trump took the action to free up billions from other sources to pay for the barrier.

Democrats have said the declaration is unconstitutional and are using a provision from the National Emergencies Act to try to halt the president.

"If the president is successful in getting his way on this, rest assured he will come back, he will try this again, probably on other issues, as will future presidents. The Congress must step up," said Rep. Joaquin Castro, the Texas Democrat leading the effort.

Hours before the vote, Trump formally threatened to veto the legislation.

House Speaker Nancy Pelosi said the core of the Constitution that lawmakers swore to uphold is the separation of powers between the three branches of government.

"Perhaps it’s time for our country to have a civics lesson," Pelosi said before the vote. "Our founders rejected the idea of a monarch."

As the resolution moves to the Senate, here's what you need to know:

Which Senate Republicans have said they’ll support the measure?

The national emergency has been controversial for Republicans, many of whom warned the president his move could set a bad precedent. But it is unclear how many will publicly oppose the president and vote to terminate the order.

On Monday night, North Carolina Sen. Thom Tillis, a Republican, announced he would vote in favor of a resolution that disapproved of the national emergency in an op-ed in the Washington Post.

"As a U.S. senator, I cannot justify providing the executive with more ways to bypass Congress," Tillis wrote. "As a conservative, I cannot endorse a precedent that I know future left-wing presidents will exploit to advance radical policies that will erode economic and individual freedoms."

GOP Sens. Susan Collins of Maine and Lisa Murkowski of Alaska have also indicated support for the measure in its current form.

Sen. Martha McSally, R-Arizona, said Tuesday night she was "seeking assurances that the money will not come from Arizona military construction projects" for her vote.

Will the resolution pass the Senate?

After passing the House on Tuesday, the resolution must be taken up within 18 days by the Senate, where its future remains unclear.

Most legislation that comes up in the Senate requires 60 votes to pass. However, because this resolution is considered "privileged," it needs just 51 votes, increasing the chances of passage. There are 47 Senate Democrats – none of whom have spoken against the resolution – so if the Democrats stay unified only four Republicans would need to cross party lines. Tillis, Collins and Murkowski already have said they would if the legislation remains the same as it was introduced.

Why does this resolution get special treatment?

Normally legislation comes up for a vote at the discretion of the speaker or majority leader. That means if a lawmaker introduces legislation the leadership doesn't want to deal with, the bill may not be brought up for a vote. But because this resolution comes from the National Emergencies Act, once it is introduced it must come up for a vote.

Are there other options?

If Congress is unable to halt the national emergency through the legislative process, members could still file lawsuits, a move Pelosi did not rule out during a press conference last week.

California and 15 other states have already filed a lawsuit over the declaration, arguing it exceeds the power of the president and unconstitutionally redirects federal money that would have gone to their states.

And the liberal watchdog group Public Citizen filed a lawsuit on behalf of Texas landowners who were told their property would be seized for the wall.

Contributing: Deborah Barfield Berry, John Fritze, Alan Gomez, Christal Hayes

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