While fucking terrible that this happened at all, at least there's this:

The decision leaves room for additional court challenges that could further slow Trump’s order, and other similar cases have already been filed. The U.S. Postal Service laid out how it would implement the order last week, but time is running short to impose major changes with some states beginning to send mail ballots to voters in just a few weeks.

The Supreme Court’s conservative majority didn’t decide the legality of Trump’s order, instead ruling that the states did not have the legal right to challenge it.

“The Court’s disposition of this application does not mean that any measure taken by the Government to implement the Order will necessarily be lawful. On that score, time will tell,” the majority wrote in an unsigned order.

Hopefully there's not enough time for the courts to further allow this bullshit. Either way, use ballot drop boxes, and if you're in a state like Washington, if you don't get your mailed ballot on schedule, you are allowed and encouraged to print it at home or at a library and drop it off in a ballot box.