Excerpts:
Americans shattered records for voting by mail in many states in the 2020 presidential election, a phenomenon that tested existing election laws, new pandemic-related regulations, postal service capacity, voter education efforts and voters’ own resolve.
Some states had more wiggle room in accepting the mail-in votes than others, allowing ballots that were postmarked by election day to come in later, anywhere from the following day to nearly three weeks after. These grace periods became a highly contentious and politicized aspect of the election. The Trump campaign and its allies challenged them all the way up to the US supreme court as part of an overall campaign questioning the legitimacy of mail-in voting.