The Supreme Court has temporarily cleared Trump's executive order on mail-in voting, a win for the White House and a headache for states trying to run the midterms.

• The order tells federal agencies to hand states a citizen list and threatens to withhold ballot delivery and prosecute election officials who don't comply.
• Lower courts had blocked it as unconstitutional because the Constitution leaves running elections to the states.
• The Supreme Court lifted that block for now, saying the states can't show real harm yet while Trump could be harmed by delay; the liberal justices dissented, noting the administration never explained how it would win on the merits.
• A separate nationwide ruling still blocks the Postal Service from following the order, so what actually happens on Election Day is unclear.
• Mail voting is also popular with older Republican voters, so the fight could cut both ways.

Outlook: More emergency appeals are coming within days, and states have to start printing and mailing ballots before the courts sort it out.