Department of Homeland Security v. Regents of the University of California, 591 U.S. 1 (2020), was a United States Supreme Court case in which the Court held by a 5–4 vote that a 2017 U.S. Department of Homeland Security (DHS) order to rescind the Deferred Action for Childhood Arrivals (DACA) immigration program was "arbitrary and capricious" under the Administrative Procedure Act (APA) and reversed the order.

[3] The University sought and received an injunction from District Court Judge William Alsup to require DHS to maintain the DACA until the case was decided.

The DACA program allowed certain individuals who entered the United States as minors to receive deferred action from deportation.

Napolitano, who served as Secretary of Homeland Security from 2009 to 2013, noted that "Neither I, nor the University of California, take the step of suing the federal government lightly, especially not the very agency that I led", but that "It is imperative, however, that we stand up for these vital members of the UC community.

[26][27][28] On January 9, 2018, U.S. District Judge William Alsup ordered the government to maintain the DACA program while the lawsuit was pending.

[4][29][30] Judge Alsup wrote that "the agency's decision to rescind DACA was based on a flawed legal premise" and noted that plaintiffs "have clearly demonstrated that they are likely to suffer serious, irreparable harm".

[32][33] In response to Judge Alsup's ruling, on January 13, 2018, the government indicated in a statement that it would immediately begin accepting DACA renewal applications using the same forms as before the program had been rescinded.

After the Ninth Circuit failed to make a decision by that date, the DOJ, on November 5, 2018, for a second time filed a petition for certiorari before judgement with the Supreme Court.

Observers at the hearing stated that the Justices appeared to stay to their ideological lines, with the conservative majority likely to side with the Trump administration.

"[2] The DHS would still be able to write an order or regulation to rescind DACA but would have to provide the necessary justification as required by the APA to validate its application.

[53] In a separate challenge to the rescinding of the DACA, Casa De Maryland v. U.S. Dep't of Homeland Sec.,[54] the Fourth Circuit ruled in May 2019, also finding that the rescinding order was arbitrary and capricious and had vacated the order but remanded the case back to the United States District Court for the District of Maryland on matters of further review.

Judge Garaufis thus ruled that Wolf's July memo was invalid, and ordered the DHS to resume the DACA program as it was, and to provide relief to those adversely affected by the temporary actions.

"[57] Yoo argued in the essay that the original DACA and DAPA programs violated the president's authority over immigration law under the Constitution as it gave this power solely to Congress, but Obama had been able to push these into practice quickly, and the only way to reverse these was through the "slow Administrative Procedure Act" that lasted through much of Trump's term, even though Trump was trying, in Yoo's estimation, to return to the Constitutionally-appropriate status.

"[58] Axios reported that they were told by White House staff that Trump and his advisors were very interested in Yoo's essay after its publication and which may be tied to the pending immigration orders.