Trump is reportedly eyeing $13.9 billion in the Army Corps of Engineers budget that was allocated in a February 2018 bill but never spent. Such funds could cover approximately 315 miles of the border wall. The bill in question provided funding for numerous disaster relief efforts, including reconstruction efforts in post-hurricane Puerto Rico and Florida, flood management projects along the hurricane-affected coastline in Texas, and numerous infrastructure projects in California, including flood protection and wildfire management. While the government remains shut down, meanwhile, all disaster relief contracts have been suspended by FEMA.

In order to reallocate the funds from the Army Corps budget, Trump would need to declare a state of national emergency. Federal law allows the president to divert funds in the case of a national emergency, which in turn was formalized through the 1976 National Emergencies Act. However, Congress can also override an emergency declaration by passing a resolution saying as much.

Trump has asked the Army Corps how quickly they could prepare and sign the contracts, reports The Washington Post. He reportedly hopes that construction could begin within 45 days. Another possible source being considered to fund the wall is drawing on the military construction budget. Nevertheless, it is widely expected that the administration would face a backlash should Trump decide to declare a state of national emergency, with several lawmakers reportedly planning to sue.

While it is still unclear whether Trump will choose to declare a national emergency, he told Fox News host Sean Hannity on Thursday that without a deal with Congress, “most likely I will do that. I would actually say I would.”

“I can’t imagine any reason why not because I’m allowed to do it,” he continued. “The law is 100% on my side.”