President Trump and son Barron board Air Force One at Andrews Air Force Base on Feb. 1. (Brendan Smialowski/AFP/Getty Images)

Congress is bracing for President Trump to target the nation’s military construction budget to build his U.S.-Mexico border wall, including money aimed at bolstering European defenses against Russian aggression.

This money would become available to Trump if he declares a national emergency to circumvent a gridlocked Congress and use the military to build his wall. An emergency declaration, which the president has hinted at repeatedly in recent days, would give him authority to tap some $20 billion from a wide array of military construction projects approved by Congress but not yet under way.

Hundreds of projects could be at risk of losing their funding to Trump’s wall — including a $60 million aircraft maintenance hangar at Marine Corps Air Station Cherry Point in North Carolina, a $105 million command and control facility at Fort Shafter in Hawaii, and a $32 million vehicle maintenance shop at Fort Campbell in Kentucky.

Lawmakers have begun raising alarms about their home-state projects getting targeted. In a news release Monday, Rep. Sean Maloney (D-N.Y.) complained about the potential for projects at the U.S. Military Academy at West Point, including a $95 million engineering center, to end up on Trump’s hit list.

“It doesn’t matter if you support building a wall or not,” Maloney said. “We can’t steal funding from the next generation of military leaders to do it.”

This type of domestic blowback, which could surface in numerous states, including some critical to Trump’s 2020 reelection prospects, has led to expectations among congressional aides in both parties that Trump could go after overseas construction projects first. A significant portion of that money is dedicated to projects that are part of the European Deterrence Initiative, an effort to help U.S. allies in Europe shore up their defenses against Russia.

The military construction budget dedicates around $800 million in the 2019 budget year toward the initiative, which was created, following Russia’s invasion of Ukraine, to bolster the U.S. presence in Eastern Europe. The money pays for staging areas, refueling stations and other efforts aimed at helping NATO allies defend against encroaching Russian threats and is considered a crucial part of the security alliance that Trump has often jeered as he suggests partner nations have not contributed enough to cooperative defense.

“For him to suggest that a border wall, where there is not an emergency, not a crisis, is more important to fund — and steal money from an account where there is certainly a crisis, because Russian aggression in Europe has been absolutely over the top — it just shows how dramatically out of touch the president is,” said Rep. Debbie Wasserman Schultz (D-Fla.), who chairs the House Appropriations subcommittee that deals with military construction. “He has no understanding or interest in our national security interests.”

Any move by Trump to dip into those overseas funds or domestic spending in the military construction budget is sure to get a hard look from Congress, lawmakers said Monday.

“The concern is, we are all trying — the White House, the Congress — to rebuild our military, and that is an area that, depending on where it came from, could undermine that goal,” said Sen. Dan Sullivan (R-Alaska), who chairs the Armed Services subcommittee that oversees military construction.

“It’s going to be a lot of tough questions by Armed Services members about where’s the money coming from, what projects is it coming out of,” said Sen. Tim Kaine (D-Va.), another committee member. “If he goes the MilCon route, the money that he’s taking is money for which there really is a need.”

Trump is pushing Congress to give him $5.7 billion to build more than 200 new miles of walls along the southern border — U.S. taxpayer funds despite his repeated promise that Mexico would pay for the wall. Democrats oppose his request, a dispute that led to a 35-day partial government shutdown that ended Jan. 25 when Trump signed a short-term spending bill containing no money for his wall.

The stopgap bill expires Feb. 15, leaving Congress less than two weeks to come up with a solution that could satisfy both the president and Democrats. A bipartisan committee of House and Senate lawmakers is working behind the scenes toward that goal, but it’s unclear if they’ll be able to reach an agreement. Trump has repeatedly dismissed their efforts as a “waste of time” because he doesn’t think they’ll agree to give him the money he wants for his wall, and he has suggested that he could end up declaring a national emergency instead.

A number of Republican lawmakers are wary about that approach for various reasons, including the precedent that would be set for a future Democratic president and the possibility that they might have to vote on a disapproval resolution aimed at overturning the emergency declaration. An emergency declaration is also considered certain to be challenged in court.

But the possibility that Trump could tap into unspent military construction or Army Corps of Engineers funds — another potential pot of money available to him under a national emergency declaration — has raised a new set of concerns, with lawmakers lobbying the president directly to try to ensure that their priorities are not touched.

After reports emerged that, under an emergency declaration, Trump could pull wall money from flood-control projects funded by the Corps after recent hurricanes, lawmakers voiced objections. Sen. Rick Scott (R-Fla.) said he spoke with Trump to ensure that Florida disaster relief would not be touched before deciding he could support Trump moving forward with a national emergency declaration.

Now, the potential for the military construction budget to be used for the wall has led lawmakers to seek similar assurances. Republican and Democratic lawmakers stressed that there is no gratuitous spending in the military construction budget — instead, there is a vast backlog of projects that do not make the list, meaning those that do are of the utmost, and most urgent, priority.

Senate Armed Services Chairman James M. Inhofe (R-Okla.) said Monday that he met with Trump about a week ago and indicated his opposition to the use of military construction funding for the border wall. He said he left with the understanding that Trump would be looking to unspent Army Corps of Engineers funds instead.

“I’ve already had a conversation with him, and I’m opposed to tapping MilCon funding; there are other Corps of Engineers fundings that could be very appropriate, and that’s what I think is going to happen,” Inhofe said, suggesting that on the basis of that assurance, he is prepared to support Trump if he decides to declare a national emergency. But, Inhofe said, “if he changes his mind, I may change my mind.”

Seung Min Kim contributed to this report