[jcranmer]

Well, you have to physically open up the envelope to pull ballots out. You have to look up the purported voter in the registration database. Check--does it exist? Does the signature match? Did the voter already cast a ballot? Get second opinions on this data for auditability purposes. And when all that's done, now you can put it in the machine. Except maybe the machine doesn't like the ballot because the ballot had to be folded to go through the postal system, so now you have to spend time flattening out the paper to get the machine to accept it.

Let's say it takes a minute to process a single ballot. That means a single poll worker can go through a couple hundred ballots--500 is a nice round number-- a day. And all of this is going to be processed generally at a centralized facility at county level, and because of the pandemic, you might have 500,000 of those to get through. Even with 100 workers working those ballots, that's still going to take 10 days to get through everything.