Secretary John Kelly pictured with a Customs and Border Patrol OfficerLate Thursday Secretary of Homeland Security John Kelly announced he was rescinding an Obama-era immigration memorandum staying the deportation of undocumented immigrants whose children are American citizens.

Deferred Action for Parents of Americans and Lawful Permanent Residents, or DAPA, never went into effect but was a target of President Trump, who promised as a candidate to revoke it as part of his broader goal of cracking down on illegal immigration.

DAPA spawned an intense legal controversy in the libertarian legal community as well as dividing the normal cast of immigration advocates and border hawks.

President Barak Obama issued his memo in November 2014, promising temporary legal status to some 4 million undocumented immigrants to allow them to get work authorizations and state benefits.

Almost immediately, 26 state attorneys general challenged DAPA, calling it an overreach of executive power and a dereliction of the president’s constitutional duty to enforce laws passed by Congress.

A Texas judge agreed with them, blocking the order from being implemented in February 2015, which ultimately sent the case to the Supreme Court.

Cato constitutional scholar Ilya Shapiro argued in an April 2016 piece for Reason that DAPA directly contradicted current immigration statutes and should be struck down.

“In our constitutional architecture, executive action based on Congress’s resistance to the president’s agenda has no place,” Shapiro wrote. “Countermanding congressional enactments is the epitome of a violation of the president’s constitutional duty to ‘take care that the laws be faithfully executed.'”

Another libertarian legal scholar, George Mason law professor Ilya Somin countered Shapiro in another Reason piece, contending the immigration statutes themselves were unconstitutional.

“The detailed list of congressional powers in Article I of the Constitution does not include any general power to restrict migration,” Somin wrote. “The Naturalization Clause gives Congress the power to establish a ‘uniform Rule of Naturalization.’ But it does not grant any authority over migration.”

Somin framed his argument as one of constitutional originalism. Without a specific grant, Congress lacks the power to regulate migration to the United States. Thus, DAPA’s deferral of deportations merely prevents unconstitutional deportations from occurring in the first place.

The Supreme Court was just as divided as the libertarian community on the question of DAPA, with a 4-4 split decision that kept the Texas injunction in place. Kelly’s action effectively ends the policy limbo.

Reactions from right and left have been fairly typical.

Tom Jawetz, Vice President for Immigration Policy at the left-wing Center for American Progress, called the decision “disappointing” and representative of the administration’s “misguided zeal to deport as many people as possible.”

On the right, Tom Fitton of Judicial Watch said on Twitter,”the restoration of our republican form of government advances” while he called on Trump to go further and “end lawless Dreamer amnesty for illegal alien children and adults.”

For a more in-depth look at the libertarian legal arguments for and against DAPA, check out this video, featuring the battling Ilyas.