Colorado Sens. Michael Bennet and Cory Gardner on Tuesday signed on as co-sponsors of the DREAM Act of 2017 after President Donald Trump announced he would phase out a program that shields young immigrants from deportation. Gardner’s support for the act is a shift for the Republican when it comes to immigration.

In 2013, Gardner voted to block President Barack Obama’s program Deferred Action for Childhood Arrivals, or DACA. During his re-election bid in 2014, the senator made immigration reform a major part of his platform. “Allowing passage of such a policy was avoiding the real problem,” Gardner told Congress in 2013. The next year, Gardner switched his position when he voted against a Republican-led effort to end DACA.

Trump said he will halt applications for the DACA program. Attorney General Jeff Sessions declared the Obama administration’s program “an unconstitutional exercise of authority” that must be revoked.

But the administration is giving Congress six months to come up with a legislative fix – “should it choose to,” Sessions said – before the government stops renewing permits for people already covered by the program.

The DREAM Act of 2017 proposes that young immigrants in the country illegally, known as Dreamers, receive conditional permanent residence followed by legal permanent status if they arrive in the U.S. before they are 18 years old; graduate from high school or obtain a GED; pursue higher education; work lawfully for at least three years or serve in the military; pass security checks; and demonstrate proficiency in English and a knowledge of U.S. history.

“Children who came to this country without documentation, through no fault of their own, must have the opportunity to remain here lawfully,” Gardner said in a prepared statement. “I’m proud to join with Senator Bennet and cosponsor the Dream Act to provide certainty to the thousands of law-abiding Coloradan Dreamers and demonstrate bipartisan leadership on this important issue. I have long called for an overhaul of our country’s immigration system and believe this is an important step. I will continue to work with Senator Bennet and our colleagues in the Senate to move this bill forward into law.”

There are an estimated 17,000 residents in Colorado enrolled in DACA; in the U.S. the estimate is 800,000.

Bennet co-sponsored the DREAM Act of 2010 and was a member of the bipartisan “Gang of Eight,” which created the bill in 2013 for comprehensive immigration reform. The bill passed the Senate but was not considered by the House.

“The Dream Act offers a promising solution amid a time of uncertainty for hundreds of thousands of young immigrants around the country – especially in light of the President’s decision today to rescind DACA,” Bennet said Tuesday in a prepared statement.

“While comprehensive immigration reform should remain a long-term solution, we also need a more immediate fix to protect Dreamers. I have long supported legislation that makes clear what we already know: supporting Dreamers boosts our economy, strengthens our national security, and aligns with our values. Congress must move quickly to pass this legislation.”

The Associated Press contributed to this story.