WASHINGTON >> Unnerving fellow Republicans, President Donald Trump declared today he would have “no problem” shutting down the federal government this fall if Congress won’t come up with more money for border security.

Trump’s threat, his second in two days, put him further at odds with his own party in Congress, where many Republicans are facing tough re-election fights this November. A shutdown when government funding expires at the end of September, just weeks before the midterm elections, would be the second under unified Republican control of Washington, following a weekend stoppage in January.

“I would have no problem doing a shutdown,” Trump said during a joint press conference at the White House with Italian Prime Minister Giuseppe Conte. “It’s time we had proper border security. We’re the laughingstock of the world.”

The president’s comments suggest he continues to believe that an election-season showdown over immigration would fire up his base and boost his party’s chances of holding power in Congress. Republican leaders disagree, hoping they can avoid a high-profile display of dysfunction and focus their message on the GOP tax cuts and the strong economy.

Trump has made no secret of his belief that his hard-line immigration policies boosted him to the Oval Office, and he launched an aggressive push for additional border security measures early this year. They include $25 billion toward construction of a wall along the U.S.-Mexico border, but he acknowledged today his demands are a starting point.

“I’ll always leave room for negotiation,” he said.

Republican leaders believed they had secured Trump’s patience last week when they huddled at the White House to discuss strategy ahead of the budget year that starts Oct.1.

After the meeting, Senate Majority Leader Mitch McConnell told a radio interviewer that a shutdown so close to the Nov. 6 midterm elections won’t happen. He said the border funding issue in particular would probably have to wait until after the elections.

House Speaker Paul Ryan said on Capitol Hill after the meeting with Trump: “The president’s willing to be patient to make sure that we get what we need so that we can get that done.” He added that money for the wall was “not a question of if, it’s a question of when.”

But on Sunday, Trump reversed course in a surprise tweet: “I would be willing to ‘shut down’ government if the Democrats do not give us the votes for Border Security, which includes the Wall!”

“Must get rid of Lottery, Catch & Release etc. and finally go to system of Immigration based on MERIT!” he tweeted.

With time so short, lawmakers appear most likely to approve a short-term funding measure to keep the government open through Election Day. That would set up another fiscal showdown during a lame duck session.

Trump today said he had no “red line” for precisely what he would require from Congress, and he made no comment on timing.

The president has pledged to campaign aggressively, starting after Labor Day, to help Republicans retain control of the House and Senate, but GOP lawmakers don’t appear to be rallying to his side this time on immigration.

Senate Appropriations Committee chairman Richard Shelby, R-Ala., said that lawmakers on both sides of the aisle are working to fund the government and that Trump’s threat “is not good for anything.”

He added: “It might help him. It might not help him. It doesn’t help us right now.”

Trump campaigned on a promise of building a wall to deter illegal immigration and to make Mexico pay for it. Mexico has refused, leading Trump to look to U.S. taxpayers to fund the endeavor instead, at least for now.

Trump has gotten some wall money from Congress, and likely will get more, though the total is well short of the $25 billion he has requested.

He also wants changes to legal immigration, including scrapping a visa lottery program. In addition, Trump wants to end the practice of releasing immigrants caught entering the country illegally on the condition that they show up for court hearings. And he wants to shift the U.S. immigration system to one based more on individual merit and less on family ties. Democrats and some Republicans have objected to those proposals.

Both chambers will have a short window to act before government funding expires at midnight Sept. 30.

The House is in recess and won’t return until after Labor Day. The Senate will stay in session for most of August, except for a weeklong break scheduled to begin Aug. 6. McConnell canceled most of his chamber’s recess to give senators time to work on the annual spending bills.

House Republicans released a spending bill this month that would provide $5 billion next year to build Trump’s wall, a plan Trump supports.

Democrats have long opposed financing the wall but don’t have enough votes by themselves to block House approval of that amount. They have the strength to derail legislation in the closely divided Senate.

The $5 billion is well above the $1.6 billion in the Senate version of a bill funding the Department of Homeland Security. The higher amount matches what Trump has privately sought in conversations with Republican lawmakers.

At last week’s White House meeting, Trump, Ryan and McConnell agreed that Congress was on track to enact more than half of federal spending before the new budget year begins Oct. 1, but that DHS funding, including the border wall money, doesn’t have to be settled before then, according to a person familiar with the meeting who was not authorized to discuss it publicly and insisted on condition of anonymity.