(CNN) — A federal appeals court said President Barack Obama’s controversial executive actions on immigration — aimed at easing deportation threats for millions of undocumented immigrants — must remain blocked.

On Monday night, the 5th Circuit Court of Appeals ruled 2-1 that a lower court did not “abuse its discretion” when it said challengers to the law were likely to succeed in their claim that the programs were unlawful because they didn’t comply with the Administrative Procedure Act (APA), a law that sets forward how federal agencies can establish regulations.

The ruling is a loss for the President — who made immigration reform a key second-term initiative. The Department of Justice said Tuesday that it disagreed with the ruling and plans to seek review from the Supreme Court.

“The Department of Justice remains committed to taking steps that will resolve the immigration litigation as quickly as possible in order to allow DHS to bring greater accountability to our immigration system by prioritizing the removal of the worst offenders, not people who have long ties to the United States and who are raising American children,” Justice Department Patrick Rodenbush said in a statement.

Under normal circumstances, in order for the Supreme Court to hear the case this term, briefing would have to be completed by mid-winter.

Texas and 25 other states had challenged the President’s authority to implement the programs.

“Immigrant families and their U.S. children have been waiting anxiously for the Fifth Circuit to rule,” said Karen Tumlin of the National Immigration Law Center. “We urge the DOJ to immediately ask the Supreme Court to review this erroneous decision.”

Details of the ruling
The 70-page opinion was penned by Judge Jerry E. Smith, a Ronald Reagan appointee, along with Judge Jennifer Elrod, who was appointed to the bench by George W. Bush.

Smith wrote, “Reviewing the district court’s order for abuse of discretion, we affirm the preliminary injunction because the states have standing; they have established a substantial likelihood of success on the merits of their procedural and substantive APA claims; and they have satisfied the other elements required for this injunction.”

Texas Attorney General Ken Paxton praised the ruling.

“Today, the Fifth Circuit asserted that the separation of powers remains the law of the land, and the president must follow the rule of law, just like everybody else,” he said in a statement.

“Throughout this process, the Obama Administration has aggressively disregarded the constitutional limits on executive power, and Texas, leading a charge of 26 states, has secured an important victory to put a halt to the president’s lawlessness.”

The President’s plan
Obama unveiled the new policies to great fanfare last November with the aim to marshal government resources and advance public safety and national security goals.

As part of the roll out, the administration established a process — called Deferred Action for Parents of Americans and Lawful Permanent Residents (DAPA) — to enable about 4.3 million otherwise removable undocumented immigrants to be eligible for work authorization and associated benefits.

The executive actions also expanded the Deferred Action of Childhood Arrivals (DACA) — a program that allows non citizens who were brought here as children to apply for work authorization and protection from deportation for three years.

Before the programs were slated to go into effect they were challenged by Texas and 25 other states. Republican governors argued the unilateral actions were unconstitutional, and that the administration also violated the APA.

DOJ lawyers countered that the actions were lawful and a “quintessential exercise of prosecutorial discretion” not subject to judicial review. They argued that Texas lacked the legal harm — or “standing” — necessary to bring the challenge.

Carolyn D. King, appointed to be bench by Jimmy Carter, wrote the dissent.

“There can be little doubt that Congress’s choices as to the level of funding for immigration enforcement have left DHS with difficult prioritization decisions,” she wrote.

She said, however, that “federal courts should not inject themselves into such matters of prosecutorial discretion.” She also criticized the majority for taking so long to issue its opinion. “There is no justification for that delay,” she said.

Elizabeth Wydra, chief counsel of the Constitutional Accountability Center, filed a brief on behalf of a bipartisan group of former members of Congress in support of the administration.

“The 5th Circuit majority misunderstands the discretion given to the executive under existing immigration law which the Supreme Court itself has explicitly recognized,” she said.

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