Former Defense Secretary Leon Panetta is urging Congress to permanently protect the hundreds of thousands of people known as "dreamers" who are protected from deportation under the Deferred Action for Childhood Arrivals program.

"Our nation's first line of defense is our people. Dreamers are part of that line of defense," Panetta wrote in a Washington Post op-ed late Monday. "[T]he best protection for dreamers would be for Sen. John McCain (R-Ariz.) to agree to allow the Bipartisan Dream Act — co-sponsored by Sen. Lindsey O. Graham (R-S.C.) and Durbin — to be attached to the National Defense Authorization Act."

The Justice Department is expected to announce Tuesday morning that the Trump administration will scrap the program after six months, which would give Congress time to write legislation protecting dreamers if it wants to.

"If Trump follows through on his threat, Congress should seize this opportunity to pass bipartisan legislation now under consideration to allow dreamers to remain," Panetta wrote. "This legislation would also help ensure that DHS spends precious immigration-enforcement resources on true security threats, such as terrorism suspects or convicted gang members — not on individuals who are willing to live here, pay taxes and contribute to society."

Panetta said he is taking a stance on DACA even though his background is in defense is because dreamers "provide an outstanding pool of young women and men who can engage in national service, including military service."

"In 2014, the Defense Department began to allow a small subset of DACA recipients with specialized skills to enter the military, following in the tradition of thousands of noncitizens who have stood up and said they are willing to fight and die for our country," Panetta added. "Today, there are several hundred DACA recipients in the Army; if DACA is ended, these soldiers could face immediate deportation."

Since being rolled out five years ago, DACA has given 800,000 people who were illegally brought to the U.S. before the age of 16 and been in the country since at least 2007 the chance to lawfully live and work in the U.S. for two-year terms.

House Republicans indicated Monday they are not interested in dealing with the issue as they mull over other pressing issues this fall, including avoiding a government shutdown later this month.