Department late Friday, blocking the department from threatening to prosecute state and local election officials who do not comply with the department’s directives on handling ballots.

The ruling by Judge Trina L. Thompson of the U.S. District Court for Northern California could deprive the department of some of its most important levers in extracting concessions from local officials — the specter of prosecution and threat of subpoenas.

The temporary restraining order was just the latest in a succession of court losses for the department in the attempt to intervene in state-administered elections to prevent illegal voting by immigrants, which is exceedingly rare.

Judge Thompson ordered the department not to “threaten, intimidate or coerce state or local elections officials or workers to demand that they halt processing the ballots” based on the government’s suspicion the voter might be a noncitizen. Her order is set to expire after Tuesday’s election. She scheduled a hearing for Monday.