The vote came hours after lawmakers in the House decided to initially weigh the question of whether or not to overturn Trump's emergency declaration earlier Tuesday, voting 229 to 193 to move to the final debate on the issue.
Trump has claimed that by declaring a national emergency, he can appropriate funds for the wall's construction.
It's the latest episode in the political melodrama that saw the US government shut down for 35 days over a refusal by Trump to sign a funding bill that didn't include $5.7 billion in border wall funding, and the Democratic-controlled House's refusal to insert such funds. However, the government narrowly avoided a second shutdown earlier this month when Congress and Trump passed a budget on February 14 that included $1.375 billion to build about 55 miles of the wall.
Trump made his declaration the following day, ensuring both that he would get the money he desired and that Congress couldn't force another embarrassing shutdown, which saw hundreds of thousands of federal employees furloughed without pay, over the issue. Trump claims his power to do this derives from the National Emergencies Act of 1976; however, that act also provides for Congress to nullify such a declaration — a power the legislature has never before invoked.
The act seeks to take funding from several other areas and redirect it toward wall construction. From the US Department of Homeland Security appropriations bill, it would take $1.375 billion; $600 million would come from the US Treasury's rug forfeiture fund; $2.5 billion would come from the Defense Department's drug interdiction program; and $3.5 billion would be taken from the Defense Department's military construction budget.
With the US House passing the measure, the Senate must now consider the resolution in the next 18 days, where Republicans enjoy a four-senator majority. However, even if the Senate passed it, too, it's certain the president would veto it, and neither house has the two-thirds majority required to override his veto.
"This isn't about the border," House Speaker Nancy Pelosi said on Monday,"this is about the Constitution.
"There is a national emergency at the southern border that the Democrats will declare today doesn't exist," House Minority Leader Kevin McCarthy said Tuesday. "The president has the authority to do it, and we will uphold him."