Federal authorities have arrested more than two dozen foreign nationals Monday in California, who authorities said have illegally registered and voted in U.S. elections. The statewide sweep is part of a Trump administration effort to root out noncitizen voting ahead of next month’s midterm elec tions, even though data shows that the problem is incredibly rare, difficult to prove and has not been shown to change the outcome of races. The arrests also reflect a further escalation in a simmering voter roll fight between the federal government and California that came into focus last week when the Justice Department sued the state and later warned that local election workers who knowingly process or tabulate ballots submitted by noncitizen voters are at risk of investigation and potential prosecution. The Justice Department said all of those arrested as part of a sweep dubbed Operation Protect the Vote are lawful permanent residents — but not U.S. citizens who are permitted to legally vote. They are charged with crimes including making false statements on a naturalization application and submitting fraudulent voter registrations. California emerges as a flashpoint for voting dispute The federal government has made noncitizen voting a priority this year, demanding detailed voter information — including dates of birth, addresses, driver’s license numbers and partial Social Security numbers — from the states. Before Monday, the Justice Department had charged about 90 people for various types of election misconduct so far this year, including 50 who are alleged to have voted as noncitizens. There were more than 227 million registered voters in the United States during the 2024 presidential election. A flurry of activity has unfolded in heavily Democratic California, which is not typically regarded as a key battleground state but does have a handful of competitive congressional races that could help determine which party controls the U.S. House for the final two years of President Donald Trump’s term. Over 23 million people are registered statewide. The administration last week sued California to prevent it from counting mail ballots from people the federal government has identified as “likely” noncitizens until their immigration status can be confirmed. The complaint was filed after California officials were given, and did not meet, a 48-hour deadline to review a password-protected thumb drive that contained a list of 20,000 names. The federal government says those are likely noncitizens who were sent ballots to participate in the Nov. 3 election, although the secretary of state said the administration has provided no evidence to support that claim. The state mails ballots to all registered voters. A warning for poll workers On Friday, the Justice Department followed up with a letter warning that state election officials who knowingly process ballots cast by noncitizen voters are at risk of investigation. “The legal consequences for either facilitating or ignoring a federal crime are significant. Noncitizen voting in a federal election is a federal crime — and knowingly facilitating such conduct is equally unlawful,” warns the letter from Trent McCotter, the acting deputy attorney general at the Justice Department. It adds: “If persons knowingly tabulate ballots cast by individuals identified by federal agencies as noncitizens, they risk becoming aiders and abettors to a federal crime.” The letter is addressed to the Los Angeles County Counsel’s office and also is copied to California Secretary of State Shirley Weber and Los Angeles County Registrar Dean Logan, effectively putting the entire state on notice. In response to the letter, Logan said his office is focused on conducting a fair and secure election while noting that Election Day is a mere 18 days away. “The U.S. Department of Justice has chosen to litigate their unverified assertions of voting eligibility. At this point, it is best for this to be addressed in court,” he said. ___ Associated Press writer Eric Tucker contributed to this report from Washington. This story was originally featured on Fortune.com ...read more read less