Susan Shelley: The Supreme Court could make election night great again

California counts votes very slowly. While many other states and even other countries can tally ballots and report totals on election night, Californians have become accustomed to waiting an entire month before the winner is known in close races.

One reason for this is a state law that requires all 58 counties to accept late-arriving mail ballots for seven days after the polls close. But that could be about to change.

Federal law (2 U.S. Code Section 7) states that there is one “day...