We may have seen it coming, but now we know for sure: The coronavirus pandemic made the 2020 election look different from any other election in recent memory. Due to the massive expansion of mail voting, a staggering number of Americans cast their ballots before Election Day. And due to then-President Donald Trump’s false claims that mail voting would lead to election fraud, a huge partisan gap emerged between ballots cast by mail and ballots cast on Election Day.First, the share of voters casting mail ballots far exceeded that of any other recent national election, and the share of voters...