Attorney General Jeff Sessions announced the revocation of Deferred Action for Childhood Arrivals on Tuesday morning, ending the Obama-era executive order and relinquishing the future of the immigration program to Congress for a six-month deliberation.

Sessions said Obama’s issuing of the executive order, which gives protections to undocumented immigrants who came to the U.S. as children, was unconstitutional, adding that it upset the balance of power between the branches of government.

“Ending the previous administration’s disrespect for the legislative process is an important first step,” Sessions said during a conference at the Department of Justice. “Congress should carefully and thoughtfully pursue the types of reforms that are right for the American people.”

Congress, which currently houses a Republican majority in both the House and Senate, will have the option of adopting legislation for DACA or letting the program expire in 2018. The latter would prevent roughly 800,000 undocumented immigrants from renewing their DACA permits, subjecting them to deportation.

President Trump hinted at Sessions’ announcement on Twitter early Tuesday morning, after previously saying he would handle DACA ‘with heart’ and that his administration “loves the Dreamers.”

Congress, get ready to do your job – DACA!

— Donald J. Trump (@realDonaldTrump) September 5, 2017

What is DACA?

The Deferred Action for Childhood Arrivals is an executive order implemented under the Obama administration in 2012. The policy allows undocumented immigrants who came to the U.S. as children prior to June 2007 to legally remain in the country for a two-year period, as well as receive a work permit.

Applicants must meet several other requirements in order to qualify for the program. Those who are deemed eligible may have their DACA permit renewed once the two-year period ends.

Opponents of the rescission

Gov. Andrew Cuomo of New York has threatened to take legal action against the Trump administration for rescinding DACA, according to Fox News. He said the program’s rescission would affect roughly 40,000 New York residents.

“If he moves ahead with this cruel action, New York State will sue to protect the Dreamers and the state’s sovereign interest in the fair and equal application of the law,” Cuomo said. “In New York, we are stepping up to protect immigrants.”

Bill de Blasio, mayor of New York City, echoed Cuomo’s sentiments.

“We’re going to the courts to fight [Trump], to stop him from taking away from the Dreamers their hopes,” he said.

Rep. Nancy Pelosi, House minority leader, also condemned the rescission in a recent statement.

“President Trump’s decision to end DACA is a deeply shameful act of political cowardice and a despicable assault on innocent young people in communities across America,” she said.

Supporters of the rescission

Ira Mehlman of the Federation for American Immigration Reform believes Congress should let the program expire.

“Our position has been that President Trump should allow DACA to lapse,” Mehlman told Fox News. “As people’s two-year deferments and work authorization expire, they should not be renewed.”

House Speaker Paul Ryan said in a statement that he supports Trump’s decision to allow Congress to act on DACA. He called the policy a “clear abuse of executive authority” by the Obama administration.

“Congress writes laws, not the president, and ending this program fulfills a promise that President Trump made to restore the proper role of the executive and legislative branches,” he said.

What does this mean for DACA recipients?

The Department of Homeland Security is currently not accepting anymore DACA applications, according to a memorandum issued on Tuesday.

Current recipients, however, will not be affected by the Trump administration’s rescission until March 5, 2018, unless Congress devises a legislative solution for DACA before that date.

Current recipients holding permits that expire before March 5 must apply for renewal before Oct. 5.