US Secretary of Homeland Security Markwayne Mullin questioned the practice of "sanctuary cities" handling customs procedures for incoming passengers during an interview with Fox News on 6/4. "We will need to seriously consider the status of sanctuary cities that continue to receive international flights, but whose local authorities are unwilling to enforce immigration policy," Mullin stated.

"Sanctuary cities" are jurisdictions where local governments, often led by the Democratic party, decline to arrest and hand over undocumented immigrants to federal authorities to prevent their deportation.

Mullin indicated he is considering restricting or withdrawing Customs and Border Protection (CBP) personnel from major international airports located in these "sanctuary cities". CBP is responsible for immigration control. If CBP forces are withdrawn, these airports would likely be unable to process international passengers entering or exiting the US.

CBP officers inspect passenger passports at a US airport. *Photo: US Department of Homeland Security*

The international airports in Los Angeles (LAX) and San Francisco (SFO), both in California, are among the largest in the US and are situated in areas the federal government considers "sanctuary cities". In 2025, SFO served over 50 million passengers, while LAX handled more than 73 million.

Mullin reiterated the idea of withdrawing CBP personnel from airports when speaking with reporters in North Carolina on 7/4. This proposal comes as the US Congress has yet to reach an agreement on funding for the Department of Homeland Security (DHS), facing opposition from Democratic lawmakers.

According to Reuters, Mullin plans to discuss the potential withdrawal of CBP forces from these airports with President Donald Trump. "If cities insist on not enforcing immigration policy, there is no reason for us to process international passengers passing through them," he said.

Mullin's stance aligns with that of his predecessor, Kristi Noem. Noem previously directed immigration law enforcement campaigns in Democratic-led cities and publicly named 500 cities, counties, and states accused of hindering federal immigration law enforcement.

In 8/2025, then-US Attorney General Pam Bondi also sent warning letters to 32 "sanctuary cities", demanding their compliance with federal immigration policy.

Last year, President Trump signed an executive order to tighten measures against cities that do not cooperate with federal immigration agencies. Mullin confirmed his intention to pursue a similar course of action.

"We will have to start prioritizing certain tasks. Remember that Democrats want to cut CBP's budget. So who will process passengers when they disembark? Therefore, I am forced to make difficult decisions to determine who is willing to cooperate with us," Mullin explained.

Security personnel at Los Angeles international airport on 27/3. *Photo: AP*

Following Mullin's statements, the office of California Governor Gavin Newsom called the idea "foolish".

"If you think the economy is bad enough with President Trump's war driving up gas prices, wait until international flights are stalled at some of the world's busiest airports," the office emphasized.

According to USA Today, if DHS were to implement this policy, it would represent a new escalation by the Trump administration to pressure "sanctuary cities".