This op-ed by National Popular Vote Chair Dr. John R. Koza appeared in The Hill on September 9, 2020:
The current state-by-state winner-take-all method of awarding electoral votes is often justifiably criticized because the candidate getting the most votes nationwide doesn’t become president; because every vote is not equal; and because candidates seek votes in only a dozen or so closely divided battleground states.
An equally serious flaw of the current system is that the national outcome is susceptible to being affected by a small number of mishandled or manipulated ballots in these decisive battleground states.
In 2020, during the pandemic, more voters than usual will rely on the post office to deliver their ballot to election officials. Mail ballots must be delivered (or at least be postmarked) by Election Day in all the battleground states. Thus, an accidentally or intentionally delayed mail truck could disqualify numerous otherwise qualified voters, thereby flipping all of a state’s electoral votes, and thereby deciding the presidency.