In the past, lawmakers have approved conditions for government shutdowns, ensuring that national security and the military are still paid despite the closure. That didn't happen during this government shutdown. So, President Donald Trump came up with a ploy to dodge Congress's decision not to approve military and national security funding.

The Government Employee Fair Treatment Act of 2019 ensured retroactive pay for federal employees affected by any appropriations lapses beginning on or after Dec. 22, 2018. It leaves them hanging in the interim, however.

CNN reported Friday that Trump has an "anonymous donor" who intends to funnel money to the Pentagon. The problem with that, however, is that it isn't legal, according to one budget expert.

“The donation was made on the condition that it be used to offset the cost of Service members’ salaries and benefits,” said Pentagon spokesperson Sean Parnell in a statement to CNN.

Parnell also said that the Pentagon took the money under the department’s “general gift acceptance authority.”

According to Trump, the donation came from "a friend of mine." It was given with the explicit purpose of being used for shortfalls.

Sen. Dick Durbin's (D-IL) spokesperson told CNN that they are seeking further information on "how this gift—and other recent reprogramming—complies with the Antideficiency Act.”

CNN explained that The Antideficiency Act stops any and all federal agencies from using money that wasn't allocated to them by Congress.

But it was a former Republican Senate budget aide who explained that this move isn't legal.

“The Antideficiency Act is explicit that private donations cannot be used to offset a lapse in appropriations,” said Bill Hoagland, who now serves as a senior vice president at the Bipartisan Policy Center.

“I think they could accept it, but they could not use it for that purpose because the law is very clear,” Hoagland added.

Read the full report here.