WASHINGTON (AP) — President Donald Trump is facing scathing criticism from conservative supporters after backing away from his threat to shut down the government over border wall funding, with some aggressively lobbying the president against signing a short-term deal with no wall dollars.

Trump has not said if he will support a temporary funding measure approved by the Senate, though his White House has made clear it will review whatever can pass Congress. Urging him to veto, Trump's critics argue he will have even less leverage when Democrats take control of the House on Jan. 3, and they worry that the unfilled pledge for a U.S.-Mexico border wall could hamper his re-election campaign.

As the chorus of discontent echoed on Twitter and Fox News on Wednesday and Thursday, the president seemed to be mounting a defense. He tweeted angrily at Democrats, declaring "I will not sign any of their legislation, including infrastructure, unless it has perfect Border Security." He also argued that border security is "tight" due to military and law enforcement efforts.

Throughout Trump's 2016 presidential campaign, "Build the wall!" was a rallying cry for his supporters. Trump supporters sought to remind him of that as they pushed him to veto the short-term plan.

On "Fox and Friends" on Thursday, Rep. Mark Meadows, R-N.C., said: ""If we're not going to fight now, when are we going to fight?"

Trump is hardly the first president to be confronted with the challenges of passing a legislative priority through Congress, but the lack of progress on an issue so closely identified with his bid for the White House may prove to be a costly failure. He had promised to begin working on an "impenetrable physical wall" along the southern border on his first day in office, but little headway has been made. A March funding bill included money for 33 miles (53 kilometers) of barrier construction in South Texas' Rio Grande Valley, but work there has yet to begin. Other work has merely replaced existing barriers that had been deemed "ineffective," not added miles.

The president's allies expressed anxiety Wednesday that Trump was, in the words of some, "caving" on the wall and warned of the potential backlash from his supporters and the impact it could have on his 2020 re-election effort. The failed promise, they argued, could weaken turnout and leave him more vulnerable to challengers.

Conservative commentator Ann Coulter published a column that called Trump "gutless" and said in a radio interview that she won't vote for Trump in 2020 if he doesn't deliver on the wall.

"Nor will, I think, most of his supporters. Why would you?" she asked, arguing that Trump's time in office will one day go down as "a joke presidency that scammed the American people."

Some within the administration cautioned that it was still possible Trump would change his mind and end up rejecting the stopgap funding bill, prompting a holiday shutdown that could also be politically damaging. Trump had said last week that he would be "proud" to have a shutdown to get Congress to approve a down payment on the wall.

Trump had originally demanded $5 billion to begin building the wall this year, but the White House acknowledged this week that he is willing to settle for far less. The temporary measure offers just $1.3 billion for border security fencing and other improvements. That money cannot be used for new wall construction.

The president had little choice. Even in the GOP-controlled House, Trump did not have the votes to get $5 billion in wall money, and House Speaker Paul Ryan declined to bring it to the floor.

The White House is instead putting its faith in a potential work-around, with Trump telling allies he'll be able to make an end-run around lawmakers by using the military to fund and carry out construction, though such a move would face significant pushback from Congress as well as legal challenges.

"Because of the tremendous dangers at the Border, including large scale criminal and drug inflow, the United States Military will build the Wall!" Trump tweeted Wednesday.

White House press secretary Sarah Huckabee Sanders said Tuesday that the president had also directed every one of his Cabinet secretaries "to look and see if they have money that can be used" for wall construction.

But Rep. Adam Smith, D-Wash., the incoming chairman of the House Armed Services Committee, told MSNBC that there has been strong opposition to using Defense Department dollars for border wall construction. And he said that Trump can't do so without lawmakers' signoff.

"Congress, both Republicans and Democrats, do not think the DoD money should go towards building a wall on the border," he said. "We have many other national security priorities that are vastly more important."

The president's conservative backers insist that Trump should not back down from his demand for $5 billion from Congress.

"Trump should not sign this bill and leave for Mar-a-Lago, and tell them it's not gonna get signed and their precious government's not gonna get back up and running 'til there's $5 billion," wrote radio host Rush Limbaugh.

On "Fox & Friends," Trump's favorite and most-tweeted-about morning show, conservative blogger Michelle Malkin described his latest move as a "cave" and a "blink."

Questioning White House counselor Kellyanne Conway, "Fox & Friends" host Brian Kilmeade said the president has "no leverage," while co-host Ainsley Earhardt asked why Trump was "softening" his position.

"The president is not softening his stance," Conway responded. "He has a responsibility to keep the government moving forward, and he has a responsibility to get border security."

Former Trump campaign adviser Barry Bennett said it was too soon to panic.

"He must have a trick up his sleeve because I can't imagine he would just walk away from it," Bennett said.

Former Republican House Speaker Newt Gingrich said that while the base would be "unhappy" if border wall funding isn't included in a final budget deal, it will make little difference come 2020.

"The other side doesn't even need a border," he said. "Their party will be so pro-illegal immigration that the choice will be enormous."

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Associated Press writers Catherine Lucey and Lisa Mascaro contributed to this report.

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