Sessions says the immigration program was an unlawful overreach by Obama that cannot be defended.

Attorney General Jeff Sessions says there will be a six-month delay in terminating it to give Congress time to act.

President Trump is ending DACA, the Obama-era program that protects hundreds of thousands of "dreamers."

President Donald Trump is ending the Obama-era program that protects hundreds of thousands of people who entered the United States illegally as children, with a six-month delay intended to allow Congress to act. Attorney General Jeff Sessions, who announced the decision Tuesday, argued that Deferred Action for Childhood Arrivals was an unlawful overreach by President Barack Obama and said he could not defend it. It sets up a potential rush for lawmakers to pass a bill protecting so-called dreamers before the Trump administration's deadline. It is unclear if the GOP-led Congress, members of which voted to sink similar legislation in the past, can do so in the near future as it faces multiple crucial deadlines to approve legislation. For his part, Trump implied in a Tuesday evening Twitter post that he hoped Congress would legalize DACA in the next six months. If lawmakers were unable to achieve that, the president said, he would "revisit" the issue. @realDonaldTrump tweet: Congress now has 6 months to legalize DACA (something the Obama Administration was unable to do). If they can't, I will revisit this issue! Public opposition to rescinding the program had mounted recently amid protests around the country. Top Republican lawmakers like House Speaker Paul Ryan and Sen. Orrin Hatch, R-Utah, as well as technology sector leaders, had pushed Trump not to scrap DACA. Trump allies like Sessions urged him to end the program, arguing it will be difficult to defend in court. "Simply put, if we are to further our goal of strengthening the constitutional order and rule of law in America the Department of Justice cannot defend this overreach," Sessions said.

Attorney General Jeff Sessions speaks during a news conference at the Justice Department in Washington, Tuesday, Sept. 5, 2017, on President Barack Obama's Deferred Action for Childhood Arrivals, or DACA program. Susan Walsh | AP

Scrapping DACA, which started in 2012 under Obama, could affect roughly 800,000 young people registered under the program. It gives the immigrants a two-year period of protection from deportation and allows them to work in the United States. Here's what the Trump administration is doing, according to the Department of Homeland Security: Acting DHS Secretary Elaine Duke has issued a memo formally rescinding DACA and starting what the administration calls an "orderly wind down."

The government will not process any new applications or requests for DACA protection.

People currently protected will not be affected before March 5, "so Congress can have time to deliver on appropriate legislative solutions," according to Duke.

Current DACA holders' protection from deportation and work permits will remain in effect until they expire, at which time they will no longer be shielded. The government will hear all pending applications for DACA protection and renewals and decide on them on a case-by-case basis. In another tweet Tuesday, Trump said Congress needs to "get ready to do your job" on DACA. He did not signal at that time what specific action he wants Congress to take in relation to the program. In a separate statement, Trump said he looks forward "to working with Republicans and Democrats in Congress to finally address all of these issues in a manner that puts the hardworking citizens of our country first." "As I've said before, we will resolve the DACA issue with heart and compassion — but through the lawful Democratic process — while at the same time ensuring that any immigration reform we adopt provides enduring benefits for the American citizens we were elected to serve. We must also have heart and compassion for unemployed, struggling, and forgotten Americans," Trump said. Conservative Republican state officials had threatened to sue the Trump administration over DACA if it had not been rescinded by Tuesday. As a candidate, Trump pledged to end the program but later softened his stance, saying he wanted to treat the immigrants with "heart." On Friday, Trump said he had a "great feeling for DACA." "We love the dreamers," Trump said, using the name for the people protected under DACA. "We love everybody." The decision could drag down the economy. A study earlier this year by the Center for American Progress estimated that the loss of all DACA workers would reduce U.S. gross domestic product by $433 billion over the next 10 years.

Congress reacts

In a statement Tuesday, Ryan criticized the Obama executive order but called for Congress to act to protect dreamers. "It is my hope that the House and Senate, with the president's leadership, will be able to find consensus on a permanent legislative solution that includes ensuring that those who have done nothing wrong can still contribute as a valued part of this great country," the Wisconsin Republican said. House Democratic Leader Nancy Pelosi called Trump's move "cruel and heartless" and said GOP House leaders should "bring the DREAM Act to the floor for a vote without delay." Arizona Republican Sens. John McCain and Jeff Flake quickly called for Congress to act on protecting dreamers. "I strongly believe that children who were illegally brought into this country through no fault of their own should not be forced to return to a country they do not know," McCain said in a statement. "I will be working with my colleagues on both sides of the aisle to devise and pass comprehensive immigration reform, which will include the DREAM Act," he added. Flake said Congress should "act immediately to pass permanent, stand-alone legislation to lawfully ensure" that dreamers can continue to contribute to the United States.

Business reacts