Remember the false slates of electors submitted by seven swing states in an attempt to replace electors chosen by the people in Election 2020? Vice-President Pence was meant to submit them in order to select Donald Trump president over the duly elected Joe Biden. When he refused to, the January 6 insurrection brought in a gallows meant to hang him.
But state legislatures could be permitted to submit alternate slates of electors. The Supreme Court heard the case Moore v. Harper on December 7, which would render Constitutional the arcane independent state legislature theory. According to this, "state legislatures enjoy nearly unlimited power to set and change rules for federal elections."
In this scenario, state courts would lose all jurisdiction over actions relevant to federal elections. For more background on the fake elector lists, read this.