WASHINGTON (AP) — President Donald Trump is trying to turn the debate over a wall at the U.S.-Mexico border back to his political advantage as his signature pledge to American voters threatens to become a model of unfulfilled promises.

Trump will hold his first campaign rally since November’s midterm elections in El Paso, Texas, today as he faces a defining week for his push on the wall — and for his presidency and his 2020 prospects. With a fresh government shutdown deadline Friday, Trump is trying to convince people he’ll continue to push to build his long-promised wall, even though there’s no way it would be anywhere near complete by the time voters have to decide whether to give him another term.

A bipartisan group of lawmakers were negotiating ahead of Friday’s deadline, but on Sunday people familiar with the talks said the mood among the bargainers had grown sour. They spoke on condition of anonymity to discuss private talks.

Acting White House chief of staff Mick Mulvaney said during news show appearances Sunday that another shutdown remained on the table, although he also said Trump probably would be willing to compromise over how much of the $5.7 billion for wall construction he’s demanded would be allocated. “Someplace in the middle,” Mulvaney said on NBC’s “Meet the Press.”

Even Trump’s full demand is a fraction of the money he needs to complete the barrier he wants. His vision for the wall already has been substantially scaled down since the 2016 campaign, when it was to be built of concrete and span the length of the border and be paid for by Mexico. Now, he’s looking to build “steel slats” along much of the 1,900-mile stretch, relying on natural barriers for the rest. The amount of federal funding he’s seeking would pay for fewer than 200 miles of new barrier.

The president, who feared a backlash from his most loyal supporters last year if he didn’t use the last gasp of unified Republican control in Washington to fight for the wall, isn’t expected to provoke another standoff with Congress. West Wing aides have acknowledged there is insufficient support among Republicans to sustain another shutdown fight.

Still, Trump has publicly dismissed the work of congressional negotiators as a “waste of time” and Sunday said he thinks Democrats want a shutdown to turn attention from the economy and other positive news for his administration.