The Deferred Action for Childhood Arrivals program, or DACA, was implemented in 2012 under President Barack Obama, and President Donald Trump's administration has continued running despite heated rhetoric against it from Trump on the campaign trail.
But DACA has arguably never been on shakier ground, and advocates for the program are desperately trying to protect it, including with a planned march Tuesday on the White House.
Nearly 800,000 undocumented immigrants have benefited from DACA, which protects individuals who were brought to the US illegally as children from deportation, and offers them the ability to work, study and drive legally. Applicants must meet certain criteria, pass a background check and maintain a clean record.
But despite the fact that the administration has continued to issue permits, concerns are increasing that the program could be ended.
"DACA is under grave threat," Nevada Democratic Sen. Catherine Cortez Masto said on a conference call with reporters Monday.
Ten state attorneys general, led by Texas Attorney General Ken Paxton, have issued an ultimatum to the Trump administration -- sunset DACA by September 5, or we'll challenge it in court. The attorneys general have threatened to petition a court that's considering a similar but separate Obama administration deferred action program, for parents, to also weigh the legality of DACA.
Experts believe that given the makeup of the court hearing the case, and its previous ruling against the parents program, the judges involved would likely strike down DACA as well.
If the court allows arguments against DACA, the Justice Department would be forced to decide whether it will defend the program. While Trump has recently spoken about how sympathetic he is to the "Dreamers" who receive DACA, saying
the choice is "very, very hard to make," he campaigned on a pledge to immediately rescind it. And the US attorney general, former Sen. Jeff Sessions, has been a chief opponent of the program.
The White House offered a cryptic statement on the program's future, expressing only concern with illegal immigration.
"The President's priority remains protecting the jobs, wages and security of American workers, families and communities -- including the millions of Hispanic and African American workers disadvantaged by illegal immigration," an administration official said.
On the call with reporters and a DACA recipient, Masto and California Democratic Sen. Kamala Harris extolled its virtues, citing estimates that the US economy would lose hundreds of billions of dollars without the contributions of DACA recipients.
"This is not just about what is morally right, this is not only a point about what is right in terms of fighting for the ideals of our country," Harris said. "This is also right and smart in terms of public benefits."
Both are co-sponsors of one bipartisan proposal to make the program permanent in Congress, the Dream Act, which also has three Republican co-sponsors. It's one of four proposed bills that would codify DACA if the administration were to rescind it or the courts were to strike it down.
The Department of Justice did not respond to a CNN request for comment.
US Citizenship and Immigration Services, the division of the Department of Homeland Security, said the program remains under review.
"The Department of Homeland Security's stance remains the same -- the future of the DACA program continues to be under review with the administration," said USCIS press secretary Gillian Christensen. "The President has remarked on the need to handle DACA with compassion and with heart. As a matter of policy, we do not comment on pending litigation, but we have said before only Congress can enact a permanent solution to the DACA situation."