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

California's attempt to block federal immigration enforcement on state property just crashed into the Constitution. A unanimous three-judge panel of the Ninth Circuit—hardly a rubber stamp for conservative causes—ruled that the state cannot prohibit U.S. Immigration and Customs Enforcement agents from operating in courthouses, jails, and other government buildings. The law, formally AB 450 and colloquially the "No Vigilantes Act," passed in 2017 with Democratic supermajorities and represented the state's most aggressive effort to obstruct federal immigration work. California had hoped to protect undocumented immigrants from deportation by simply making it illegal for ICE to operate there. The Supremacy Clause had other ideas.

What made this ruling stinging wasn't that conservatives won—it's that the Ninth Circuit, which California progressives often cite as an ally, sided unanimously against the state's immigration sanctuary. The court found no constitutional wiggle room: when Congress gives ICE the authority to enforce federal immigration law, states cannot use their property or police power to create de facto zones where that authority vanishes. California tried arguing that the law merely restricted access to state property, a property-rights issue—a clever framing that didn't survive judicial scrutiny. The opinion essentially said states cannot use property ownership as a cudgel to nullify federal law, which is what Supremacy Clause jurisprudence has held since Marbury v. Madison.

The immediate stakes are procedural but profound: ICE agents can now conduct operations inside California courthouses and county jails without running afoul of state law. This means undocumented immigrants appearing for traffic violations or small offenses now face the genuine risk of deportation during their courthouse visit—a reality California's Democratic legislators had explicitly tried to prevent. For the roughly 2.3 million undocumented immigrants in California, the ruling closes what had become a crucial safe harbor. For ICE, it restores a standard enforcement tool that California had cordoned off for five years.

The conservative read here doesn't require partisan cheerleading: a state government attempted to nullify federal law through property restrictions, and the courts—even progressive ones—recognized this as constitutionally indefensible. This is textbook federalism. Congress passed immigration statutes, the executive branch executes them, and California cannot simply declare certain geographic zones federal-free. The law's architects knew exactly what they were doing: they hoped to make ICE's job sufficiently difficult that enforcement would effectively stop. It didn't work. What's notable is that this wasn't a 5-4 Supreme Court decision split along ideological lines. The Ninth Circuit's unanimity suggests the legal case was airtight, and even judges appointed by Democratic presidents found no constitutional shelter for California's gambit.

Watch for California's next move in the coming weeks. State Attorney General Rob Bonta has already signaled continued resistance to ICE cooperation, and Democratic legislators will likely explore whether they can craft workarounds that survive this ruling—perhaps limitations on information-sharing or restrictions on when ICE can access jail holding areas. The real test comes when ICE actually increases courtroom arrests and California's immigrant advocacy groups demand state officials obstruct enforcement through means other than direct prohibition. The ruling closed one legal avenue but the political battle over sanctuary is far from over.