What 'safe harbor day' is and why it's bad news for Trump

"Assuming that the pending federal court litigation does not give the plaintiffs any of the remedies they are seeking, these federal cases should not affect safe harbor status, even if they go past Tuesday," said Edward Foley, an election law expert at Moritz College of Law at the Ohio State University.

https://www.nbcnews.com/politics/2020-election/what-safe-harbor-day-why-it-s-bad-news-trump-n1250205