California has some 23 million people on its voting register. As of Sunday night, more than six million mail-in ballots had already been received, according to the California secretary of state’s office.
The one-line order left standing rulings from two lower courts and a federal appeals court that had already rejected the request, effectively ending the Trump administration’s effort to disqualify those ballots in the nation’s most populous state.
The legal push formed part of a years-long campaign by President Donald Trump and his administration against alleged voter fraud they contend is widespread. Research has found such fraud to be extremely rare.
On Friday a federal appeals court declined the government’s request to isolate the ballots. Two lower courts had previously rejected it.
State officials had already challenged the process used to identify alleged non-citizens as inaccurate.
California election officials questioned the accuracy of the federal claims and said the list of names provided by the government was riddled with inaccuracies. They warned that eligible voters could be disenfranchised. Officials also said it was unfeasible to segregate ballots while voting was already under way.