I’ll give an example:
Trump carries Michigan. And, crucially, with this state, wins the election. But Michigan dallies, never certifies the vote and doesn’t appoint Electors. Therefore, Biden wins because he has a majority of the EVs who are appointed.
What is crucial is that Michigan is a (currently) Democrat-CONTROLLED state won by Trump.
What if in 2016, Trump lost Pennsylvania (20 EV) and Wisconsin (10 EV)? That would have made the Electoral College 276-262, and Trump would still have won.
Now suppose that Michigan (16 EV), which Trump won 47.6% to 47.4%, politically chose to delay certifying the vote and not send their Electors to the Electoral College. This would have made the Electoral Vote 262-260 Clinton in an Electoral College with only 522 appointed Electors. The threshold to win would have been a majority of APPOINTED Electors, or 262.
Clinton would have won in 2016 in this scenario, because Michigan chose to withhold their 16 Trump Electors from participating in the Electoral College.
That's the scorched earth scenario the Democrats are probably gaming.
-PJ