Nearly 7 million absentee votes were cast, mostly for Joe Biden, in the three states responsible for his presumptive win; a mere 250,000 votes now separate Biden from Donald Trump in Michigan, Wisconsin, and Pennsylvania.Trump’s victory in that once solid “blue wall” in 2016—Wisconsin last elected a Republican president in 1984—shocked the nation and elevated him to the presidency. The pivotal Rust Belt states have something else in common: according to state election laws, mail-in ballots cannot be processed prior to 7 a.m. on Election Day. (Michigan has a slight caveat for larger cities, which allows ballot inspection to begin...