WASHINGTON — President Donald Trump has long said that he wants to shut the government down as a means to force Democrats to fund the border wall he initially promised would be paid for by Mexico.

"If we have to close down our government, we're building that wall," he said in July 2017.

Until now, he has held off. But with operating authority for several federal agencies due to expire Dec. 21, the president is finally ready to grant his own wish.

After Trump invited reporters to sit in for a testy exchange at his first meeting in more than a year with Senate Minority Leader Chuck Schumer and House Minority Leader Nancy Pelosi on Tuesday, the Democrats teed him up to shoulder the credit or the blame if the money runs out and the government is forced to close down.

Pelosi, a California Democrat who is expected to become House speaker in January, referred in the meeting to a partial government closure as the "Trump shutdown."

Schumer, a New York Democrat, told Trump "you want to shut it down. You keep talking about it."

Trump took the bait.

"If we don't get what we want, one way or the other ... I will shut down the government. Absolutely," he said. "I am proud to shut down the government for border security."

Later, Trump told reporters that he was happy to take responsibility for a partial pause in government operations. It was "Chuck's problem" when the government briefly shut down early in the year, Trump said.

"It was his idea, and he got killed," Trump said, either unaware or unconcerned that he was putting himself in the same position as Schumer was in less than a year ago. "He doesn't want to own it."

"I'll take it," Trump added. "I will take it because we're closing it down for border security, and I think I win that every single time."

Many of his most ardent supporters hate government spending and love the wall. So, from the perspective of pleasing a base that is frustrated that the centerpiece of his 2016 campaign platform has been stalled — no matter that the president continues to describe it as well underway — it makes sense for Trump to do both.

But there's reason for Republicans who care about the broader public perception of the party's ability to govern and to expand its base to worry about his tactics.

Rep. Tom Cole, an Oklahoma Republican who serves on the House Appropriations Committee, said most GOP lawmakers agree with Trump on border security policy but that even the president has taken note of the hit Democrats took when they were blamed for the shutdown.

"I don't see the advantage of playing this card in reverse," Cole said in a telephone interview with NBC News.

Like Cole, many Republicans on Capitol Hill aren't nearly as excited as Trump about the prospects of a partial government shutdown — several agencies, including the Defense Department, are already funded through the end of the fiscal year in September — right before Christmas.

"I hope that's not where we end up," Senate Majority Leader Mitch McConnell, R-Ky., told reporters in the Capitol on Tuesday. "I'd still like to see a smooth ending here, and I haven't given up hope that that's what we’ll have."

Michael Steele, a former chairman of the Republican National Committee and a frequent Trump critic, said that the president is setting the GOP to take a hit with voters.

"There's no way that you're going to be able to sit down, with that on videotape (Trump pushing for a shutdown), and blame the Democrats for a shutdown," he said. "I can tell you the leadership is not happy about that. They know the consequences of these things. They do have a way of coming back to bite that you see at the ballot box."

Trump is still obsessed with the midterm elections, but his attention — and that of fellow Republicans — will soon turn to 2020.

He has to weigh whether the pain of being blamed for a shutdown is worth the chance that it will result in him getting something that resembles the border wall he promised. With Democrats in control of the House for the next two years, that will be a tall order.

Meanwhile, House Republicans will have to pick up at least 17 seats to take power back from Democrats after losing ground in each of the last two elections and with a president whose approval rating has been mired below the break-even point in Gallup polling for the entirety of his term.

In the Senate, Democrats are eyeing potential gains in Arizona, Maine and Colorado, while the most likely target for Republicans is Sen. Doug Jones in Alabama. Polling and recent election results in Arizona, Maine and Colorado suggest that Trump's border wall isn’t popular in those states.

Overall, Americans say, by a 57 percent to 36 percent margin, that Trump should make concessions on his border wall to prevent a government shutdown, according to a recent survey by NPR, PBS NewsHour and Marist College.

Cole said the two sides have basically reached agreement on everything but the level of funding for border security in the Homeland Security bill and how that will be allocated to an actual wall or other methods of deterring illegal immigration.

"This, to me, is more about politics than it is about substantive policy," he said. "But it's supercharged because of the politics."

The question is whether Trump's drive to shut down the government over the border wall is good politics for the GOP.