With mail-in voting under threat, election officials say Washington voters should use drop boxes or mail ballots a week before Election Day

Even if the high court doesn't strike down a Mississippi law and others like it that allow late-arriving ballots to be counted, Sen. Maria Cantwell warned Tuesday that Washington voters could see their ballots rejected this fall because of a U.S. Postal Service policy change that took effect in December. Under the new rule, mail is postmarked when it…