Part of Trump’s grand plan is to make federal elections span only a single day.

Don’t see the problem. For years in Italy elections were a one day only events (normally a Sunday) and everything worked fine.

So maybe you check your status the day before and everything is fine, but the day of voting a glitch in the system says it can’t verify your citizenship. That’s it! No votes for you this year!

There are solutions since the system need to be resilient, note that the glitch could be even not “wanted” so while you can think that $HATED_CANDIDATE want to keep his opponents away from the voting, in the same way $HATED_CANDIDATE want to make sure that his supporters can vote.