Zach Montellaro for Politico:

Michigan, Pennsylvania and Wisconsin are expecting huge surges in ballots cast by mail in 2020, like most states preparing to vote during the coronavirus pandemic. But all three Midwestern battlegrounds, which President Donald Trump flipped in 2016 to win the White House after years of Democratic presidential victories there, are among the states where local election officials are not allowed to start processing mail ballots until Election Day, according to a POLITICO review of election rules in 13 key states.

Mail ballot processing involves everything from opening envelopes to checking voter signatures to flattening ballots that have been crumpled or creased in transit. The procedures can be time consuming, and that will create a backlog of millions of votes set to draw out the counting process for days after the polls close.

That means that the country may be waiting, along with voters in the three Midwestern states, to see whether Trump or Joe Biden carried their electoral votes — and potentially the presidency.

“People kind of underestimate the enormity of that task,” said Ohio Secretary of State Frank LaRose, a Republican, as he ticked through the long processing checklist that each ballot must go through before it can be counted. LaRose’s state, unlike many of its neighbors, lets election authorities start processing ballots earlier. “God forbid we had to do all of that on election night.”