Department of Homeland Security Secretary Markwayne Mullin told Fox News on Monday that the Trump administration is weighing whether to end customs processing services at airports in cities that refuse to cooperate with federal immigration enforcement, a move that could effectively halt international travel at some of the busiest hubs in California.
The proposal, if carried out, would pull U.S. Customs and Border Protection officers from airports in sanctuary cities. Without those officers, no international passenger can be processed into the country. That means no arrivals, no departures requiring customs clearance, and potentially no Global Entry service at airports like San Francisco International, Los Angeles International, San Diego International, and Oakland International.
Mullin did not mince words about the logic behind the idea. In his Fox News interview, the new DHS secretary framed the potential action as a direct consequence of sanctuary policies that block local law enforcement from working with federal immigration agents.
"Seriously, If they're a sanctuary city, and they're receiving international flights, and we're asking them to partner with us at the airport, but once they walk out of the airport they're not going to enforce immigration policy, maybe we need to have a really hard look at that because we need to focus on cities that want to work with us."
That is not a vague warning. It is a sitting cabinet secretary describing, on the record, a policy the administration is actively considering.
CBP agents operate at more than 300 ports of entry across the country, including international airport terminals. At major California airports, LAX, SFO, SAN, and OAK, those agents are the only personnel authorized to process arriving international passengers through customs. Remove them, and the terminals go dark for international flights.
The San Francisco Chronicle reported that travel at SFO would "effectively halt" if the threat materialized. Long lines and cascading delays would be the mild version. The more realistic outcome: airlines would have no reason to schedule international service into airports where no one can legally clear passengers.
The California Post reached out to both LAX and SFO for comment. Neither airport's response was reported. Governor Gavin Newsom's press office, however, had plenty to say, on X.
On April 6, Newsom's press office posted a response dismissing the proposal. The post read, in part: "If you thought the economy was bad with Trump's war driving prices at the pump up... just wait until international travel is halted at some of the busiest airports in the world."
The post went on to call it "a stupid idea (no wonder it's being considered by the Trump Admin)." When The California Post contacted the governor's office directly, a spokesperson said only that "the post on social media speaks for itself."
That is the full extent of California's official response to a threat that could reshape the state's aviation economy: a social media post and a shrug. No policy counter-offer. No signal of willingness to negotiate. No acknowledgment that the state's sanctuary posture carries trade-offs.
The contrast is worth sitting with. The federal government says it needs local cooperation to enforce immigration law. California says no. The federal government says it may stop providing federal services that depend on that cooperation. California calls it a "stupid idea" and moves on. Somewhere in between are the millions of travelers, airline workers, and businesses that depend on those airports running.
Mullin's warning fits squarely within the administration's broader strategy of applying financial and operational pressure to jurisdictions that obstruct immigration enforcement. President Trump himself laid out the framework during a speech in Detroit.
"Starting February 1, we're not making any payments to sanctuary cities or states having sanctuary cities because they do everything possible to protect criminals at the expense of American citizens."
That directive targeted federal funding. The customs proposal goes further, it targets federal services. The administration's argument is straightforward: if a city refuses to enforce immigration law once travelers leave the airport, why should the federal government staff the airport to process those travelers in the first place?
The logic has a certain blunt coherence. Sanctuary cities want the benefits of federal infrastructure, customs processing, Global Entry kiosks, CBP staffing, without accepting the obligations that come with federal immigration cooperation. The administration appears ready to test whether that arrangement can survive without both sides holding up their end.
This is not the first time DHS has flexed operational muscle at airports. During the partial government shutdown, the Trump administration deployed ICE agents to airports across the country to relieve the strain caused by a shortage of TSA workers. SFO, notably, was not affected by that move because it contracts its own TSA screening agents, a detail that underscores how federal staffing decisions can hit some airports harder than others.
California's sanctuary policies have been a point of friction with the federal government for years. But the stakes have escalated sharply under the current administration. Congressional efforts like the Protect America Act have sought to impose penalties on jurisdictions that shield illegal immigrants from federal authorities. The customs threat represents the executive branch's version of the same principle, applied not through legislation but through the withdrawal of services.
Mullin, who was tapped to lead DHS after the department faced a prolonged standoff with Democrats over ICE operations, has shown no hesitation in pressing the confrontation. His appointment signaled that the administration intended to escalate, not retreat, on immigration enforcement.
The question now is whether the administration will follow through or whether the customs proposal stays in the realm of leverage, a warning shot designed to bring sanctuary jurisdictions to the table. No formal policy, memo, or executive order has been issued. Mullin described the idea as something the administration is "looking at," not something already in motion.
But the distinction between a threat and a policy can collapse quickly. And the administration has shown, across multiple fronts, that it is willing to use every available lever to force compliance on immigration.
If customs officers are pulled from California's international terminals, the people who suffer first are not politicians. They are travelers, airline employees, small-business owners near airport corridors, and the broader tourism and trade economy that depends on international connectivity. LAX alone is one of the busiest international gateways in the Western Hemisphere.
Sanctuary-city advocates will frame this as federal overreach, the government punishing ordinary people for the policy choices of elected officials. And there is a real cost to disrupting air travel at this scale.
But the question cuts both ways. Sanctuary policies also impose costs, on communities dealing with illegal immigrants who cannot be removed, on federal agents whose work is obstructed, on victims of crimes committed by individuals who should have been detained. The administration's position is that those costs have been borne quietly for too long, and that the cities responsible should feel some consequences too.
Governor Newsom's office could engage with that argument. It could propose a compromise, or at least acknowledge the tension. Instead, it posted a quip on X and told reporters the post "speaks for itself."
The federal government has already signaled a willingness to reassert its presence in San Francisco and other California cities. The customs proposal is the sharpest version of that message yet.
Several details remain unclear. DHS has not specified whether "ending customs processing services" means a full withdrawal of all CBP officers or a reduction in certain services. It has not named every city or airport that could be affected beyond the California examples. And no timeline has been attached to the proposal beyond Mullin's statement that the administration is considering it.
Whether this becomes policy or stays a pressure campaign, the underlying dynamic is plain. The federal government provides services that sanctuary cities need. Those cities refuse to cooperate with the federal government on immigration. The administration is now asking, publicly and pointedly, why that arrangement should continue.
California's leaders can call it a stupid idea. But sooner or later, someone has to answer the question.