Can state or federal courts order post offices to postmark absentee ballots? To stay open late on election day?

More unanticipated consequences from Republican National Committee v. Democratic National Committee

On April 6, the Supreme Court decided Republican National Committee v. Democratic National Committee. This case held that absentee ballots in Wisconsin would be counted if they were "postmarked by election day." The Washington Post reports there was a "unexpected outcome" from this decision:

Because of the order, election officials for the first time tallied absentee ballots postmarked by Election Day, rather than just those received by then — underscoring the power of narrow court decisions to significantly shape which votes are counted.

Now, the Democratic Party is seeking to extend the Roberts Court's latest ruling. (Yes, you read that right):

Democrats think they have secured a game-changing precedent from the Supreme Court's 5-to-4 order. In the past week alone, lawsuits bankrolled by Democratic committees have been filed in four states seeking similar postmark rules and citing the Wisconsin opinion to bolster their argument. More cases are expected in the coming week….

Now, Democrats are citing the majority opinion in their latest round of litigation.
In addition to seeking postmarked-by standards, Democrats are aiming to secure free postage for ballots, ballot mailings to all registered voters and the right for third parties to collect ballots from voters, a controversial practice often called ballot harvesting.

"We're saying, essentially, let's take into account the pandemic. Let's keep everybody safe," said Eric H. Holder Jr., who served as attorney general in the Obama administration and heads a group that is financing new lawsuits in Texas and North Carolina.

May I speculate about another unanticipated consequences of RNC v. DNC? Interested parties will litigate to ensure the United States Postal Service postmarks more ballots. The Washington Post observed that some ballots were not postmarked at all:

Thousands of ballots were rejected because of postmark issues, The Post's examination found. Hundreds were rejected because of a late postmark, but many hundreds more showed no postmark or an illegible one. In Milwaukee, that number was 390, and city election officials chose to count those ballots anyway. Most other localities discarded such ballots, even though many may have been posted on time.

Several election officials said that some post offices do not use postmarks with dates but that their hands were tied by the high court's ruling.

In a statement, the U.S. Postal Service said its inspector general is conducting an investigation "regarding potential issues with absentee ballots in Wisconsin."

Interested parties, I'm sure, will sue the USPS to ensure that ballots are postmarked properly. And what about illegible postmarks?  Courts will have to decide how to assess the validity of various smeared postmarks. Say hello to the new hanging chads!

And what about election day? Interested parties routinely seek injunctions to keep polling locations open late. The usual rule: if you are in line, you can vote. Why not similar injunctions for post offices? Keep the postoffice, and the postmarks stamping till midnight, or later, to ensure late-delivered ballots are marked.

The Supreme Court may have unintentionally opened up a new frontier in election law.

And there are two unanswered questions in my mind. First, can a state court judge even issue an order to a federal postal official? McCulloch on the mind. Second, would a federal court have jurisdiction over state election law disputes?

Everyone, please think these issues through now, well before election day. You're welcome.