Why switching to voting by mail for the 2020 presidential elections could disenfranchise millions

The Covid-19 pandemic has struck as America gears up for the 2020 presidential election. With restraints on social interactions now in place, a move to nationwide voting by mail has been suggested as a way to conduct the election fairly. Peter Miller writes that voting by mail has become more popular, especially in western states, but that this has taken time – time that we now do not have. He warns that there are many ways mail-in ballots can be invalidated, and that previous studies show that they are much less likely to be counted than those cast in person