A staffer for a California Democratic assemblywoman, a former Chinese-language news anchor, was taken into custody by federal immigration authorities at a Las Vegas airport after allegedly overstaying his visa by more than five years.
Ho-Yin Mo, who joined the office of California Assemblywoman Catherine Stefani this year, was arrested Thursday at Harry Reid International Airport by Department of Homeland Security agents, the New York Post reported. DHS told The California Post that Mo had entered the country lawfully on January 13, 2020, on a temporary basis but "illegally overstayed his welcome by failing to depart by May 15, 2020."
That means Mo had been living in the United States without legal status for roughly five years before federal agents caught up with him at the airport. During that stretch, he built a public career, first as a news anchor at KTSF, a Chinese-language television station in San Francisco, then as a political operative for prominent California Democrats.
Mo's path from expired visa holder to Democratic staffer ran through some of San Francisco's most visible political circles. In 2024, he worked as an outreach organizer focused on Asian American and Pacific Islander communities for London Breed's unsuccessful mayoral reelection campaign. Joe Arellano, a spokesperson for Breed, praised the hire at the time.
Arellano told reporters:
"When we learned that Mo was available, we immediately saw an opportunity to bring him on board. His visibility through KTSF connects with a broad audience, and his professional background and experience made him a strong fit."
That "visibility" apparently did not prompt anyone on the campaign to verify whether Mo was lawfully present in the country. After Breed's reelection bid failed, Mo landed in Stefani's office in 2025. Stefani represents California's 19th Assembly District, which covers western San Francisco and northern San Mateo County. She previously served on the San Francisco Board of Supervisors from 2018 to 2024.
Her office did not return a request for comment from The California Post about Mo's arrest or whether anyone had checked his immigration status before putting him on the public payroll.
The federal government has stepped up enforcement efforts against illegal immigrants across the country, including those who entered lawfully but failed to leave when required. ICE agents have arrested noncitizens in a range of settings, from routine traffic stops to airport encounters like Mo's.
DHS addressed one argument that visa overstays sometimes raise in their own defense. The agency stated plainly:
"Work authorization or a pending application do NOT confer legal status in the United States."
That distinction matters. Some illegal immigrants who overstay visas obtain work permits or file immigration applications and then claim those filings give them a right to remain. DHS's statement shut that door. A work permit is not a green card. A pending application is not approval. And neither one makes an overstay legal.
Mo's case raises an obvious question: did Stefani's office or Breed's campaign verify his eligibility to work in the United States? Federal law requires employers, including government offices, to confirm that employees are authorized to work through the I-9 process. Whether Mo held some form of work authorization despite lacking legal immigration status remains unclear from available reporting. But DHS's pointed statement suggests the agency anticipated exactly that line of defense.
The broader pattern of noncitizens embedding themselves in American civic life without legal status has drawn increasing federal scrutiny. The Justice Department has pursued cases against noncitizens who registered to vote, and immigration agents have expanded operations at airports and other transit hubs.
What makes Mo's case stand out is how visible he was. He was not hiding in the shadows. He appeared on television as a news anchor at KTSF, one of San Francisco's established Chinese-language stations. He worked on a high-profile mayoral campaign. He joined a state legislator's staff. At every step, he operated in public, while DHS says he had no legal right to be in the country at all.
The timeline is stark. Mo's temporary authorization to remain in the United States expired on May 15, 2020, just four months after he arrived. From that date forward, every day he spent in the country was, in DHS's telling, a violation of federal immigration law. Yet he spent the next five years not only staying but building a career in media and Democratic politics.
Some lawmakers have pushed to strip funding from the very agencies responsible for enforcing immigration law. Rep. Ilhan Omar introduced legislation that would redirect billions away from ICE and toward immigrant communities, a proposal that, if enacted, would make cases like Mo's even harder to pursue.
No formal charges against Mo have been publicly detailed beyond the visa overstay allegation. His current custodial status following the arrest is not clear. The specific immigration enforcement unit within DHS that conducted the arrest, whether ICE, Customs and Border Protection, or another component, has not been identified in reporting.
What is clear is the gap between California Democrats' rhetoric on immigration and the reality that played out inside their own offices. Stefani's district sits in one of the most progressive corridors in America. San Francisco has long positioned itself as a sanctuary for immigrants. But there is a difference between welcoming immigrants and failing to notice, or failing to care, that a staffer on the public payroll had no legal right to be in the country.
Federal enforcement actions have also exposed cases of noncitizens with criminal records participating in elections, further underscoring how porous systems can be exploited when verification is treated as optional.
Meanwhile, debates over how government resources should be allocated continue at every level. Proposals to restructure public spending, from welfare reform to immigration enforcement budgets, remain politically charged, and cases like Mo's add fuel to the argument that basic compliance checks are being neglected while politicians chase broader policy ambitions.
Stefani's refusal to comment is notable. A sitting assemblywoman's staffer gets arrested by federal agents at an airport, and her office has nothing to say. No statement of concern. No explanation of its hiring process. No indication of whether it knew about Mo's status or bothered to ask.
That silence fits a pattern. In California's progressive political ecosystem, immigration enforcement is treated as an imposition rather than a legal obligation. Sanctuary policies, limited cooperation with federal agents, and a general posture of resistance to immigration law have created an environment where someone like Mo can move through public life for years without anyone in a position of authority raising a flag.
If a state legislator's own office cannot be bothered to verify that its employees are in the country legally, voters in the 19th Assembly District are entitled to ask what other corners are being cut, and who is ultimately accountable when the system fails this plainly.
