WASHINGTON — A White House meeting between President Donald Trump, Senate Minority Leader Chuck Schumer, and House Speaker–designate Nancy Pelosi quickly devolved into an open, chaotic argument over the border wall on live television Tuesday.

The spat ended with Trump threatening a partial government shutdown right before the holidays if he doesn’t get his border wall.

“If we don’t get what we want, one way or another … I will shut down the government. And I am proud to shut down the government for border security, Chuck,” Trump said. “So I will take the mantle. I will be the one to shut it down. I’m not going to blame you for it. The last time you shut it down, it didn’t work. I will take the mantle and we’ll shut it down.”

Schumer quickly responded, “We believe you shouldn’t shut it down.”

The point of the meeting was to discuss border security funding ahead of a Dec. 21 deadline when part of the federal government, including the departments of Homeland Security, Justice, and State will shut down if a spending bill is not passed. Trump cannot shut down the entire government, however. Congress has already passed and Trump has signed funding bills for many other federal departments — including the departments of Defense, Health and Human Services, and Veterans Affairs — insulating them from a shutdown before the holidays.

When government shutdowns occur, the affected agencies don’t completely close, but they operate at reduced levels. Federal employees whose function is deemed essential (such as US Border Patrol agents) continue to do their jobs, but nonessential employees are not allowed to work. Shutdowns also create uncertainty for some federal employees because they don’t get paid and it’s not immediately clear whether they will be paid again.

At the top of the agenda for Tuesday’s meeting was the border wall, a campaign promise for which Trump requested $5 billion. Democrats are not willing to spend that much, and the wall remains the major item in dispute ahead of the funding deadline.

Trump dug in on the idea of building the wall — which he originally promised Mexico would pay for — even as the political reality of it will become less feasible as Democrats take over the House next year.