California’s justices will return early from recess next week to weigh whether the state attorney general can override a county sheriff and shut down a voter fraud investigation, in a dispute with implications for November’s election security.

The state high court will consider whether Riverside County Sheriff Chad Bianco had the authority under a judicially-approved warrant to seize 650,000 local ballots cast in California’s statewide vote on its Proposition 50 redistricting measure. Bianco intended to investigate voter fraud allegations — even after Attorney General Rob Bonta (D) ordered him to stop.

The dispute before the court will likely set new …