Gavin Newsom’s legislative minions just got a lesson in constitutional supremacy

A three-judge panel of the Ninth Circuit Court of Appeals—not typically known for constraining state power—just delivered a sharp rebuke to California's attempt to handcuff federal immigration enforcement on state soil. The "Defend California Act," passed in 2017 and strengthened via SB 54 in 2024, prohibits state and local law enforcement from using resources to help ICE agents conduct immigration enforcement, and bars them from cooperating with federal detainers unless backed by a warrant signed by a judge. Last week's unanimous decision found these restrictions unconstitutional under the Supremacy Clause because they obstruct federal immigration policy. The ruling applies immediately to all California law enforcement agencies—roughly 8,000 police departments statewide that had aligned with Sacramento's sanctuary framework.

What makes this particular loss stinging for Newsom is the unanimity. When a court this ideologically heterodox agrees—and the Ninth Circuit has three Trump appointees on the three-judge panel—it signals the legal ground beneath California's position has crumbled entirely. The practical stakes are immediate and concrete. ICE agents operating in California have been forced to navigate a patchwork where local police won't verify immigration status during routine traffic stops or confirm detainers even when a person sits in custody. That friction has measurably slowed deportation operations: ICE arrests in California dropped from roughly 13,000 annually before SB 54 to under 3,000 in recent fiscal years. Now, federal agents regain the ability to coordinate directly with local law enforcement, at minimum through information sharing and facility access.

The constitutional framework here is unambiguous. The Supremacy Clause means states cannot pass laws that directly conflict with federal law or hamstring federal agencies executing their statutory mandates. California's law didn't just decline to help—it affirmatively prohibited cooperation in cases where federal law explicitly authorized it. The Ninth Circuit found that Congress, through the Immigration and Nationality Act, has given ICE broad authority to enforce immigration law within the states. When Sacramento criminalized state officer participation in that enforcement, it crossed from policy disagreement into constitutional violation. The court noted there's a difference between refusing to deputize state resources for federal purposes (which states can do) versus prohibiting all cooperation, even voluntary information exchange (which they cannot).

The conservative read is straightforward: Newsom spent years and legislative capital building a sanctuary regime that positioned California as a counterweight to federal immigration authority, and he just lost in a way that strips away the legal pretense. This wasn't about states' rights or federalism—it was about California using state power to nullify federal law. The Supremacy Clause exists precisely to prevent states from doing this, and the court simply enforced it. Newsom now faces a political choice: appeal to a Supreme Court that has shown even less patience for immigration-related state obstruction than the Ninth Circuit, or watch his signature immigration policy unravel. The real story here is that the administration bet it could use state bureaucracy as a tool to block federal enforcement, and it lost on the merits.

California could petition the full Ninth Circuit for an en banc rehearing, though given the panel's unanimity, that's a long shot. More likely, the state will file a cert petition to the Supreme Court sometime in the next 60 days, knowing that the current Court majority is skeptical of state-level immigration obstruction—Chief Justice Roberts sided with conservatives on Arizona's immigration provisions in 2012, before the Court moved further right. If the Supreme Court declines review, the ruling becomes final and California agencies face immediate pressure from ICE to cooperate on detainers. If the Court takes the case, expect oral arguments in the 2025 term. The real leverage point for Newsom is Congress—passing legislation that explicitly protects state sanctuary policies would override the Supremacy Clause analysis. Short of that, watch whether ICE actually changes operational tactics in California or whether the agency faces political pressure not to exploit the ruling.