Jon Ward for Yahoo News:

Anyone can spin out a worst-case scenario for the presidential election, but it’s worth paying particular attention to those that keep experts like Richard Hasen up at night.

Hasen, a law and political science professor at the University of California, Irvine, has written multiple books on elections, including one that was released just before the COVID-19 pandemic, “Election Meltdown.”

Even before the pandemic made it likely that there will be a historic number of mail-in ballots in this fall’s election, Hasen was worried that if the election were close, President Trump might declare victory before all the votes were counted.

That concern is now much greater for Hasen. Since the emergence of the coronavirus, Trump has made numerous wild claims — without any evidence and in contradiction to known facts — that mail-in voting will lead to widespread fraud and cheating.

If most Republicans vote in person and most Democrats vote by mail, Hasen said, that could create a scenario well suited to Trump’s tendency to make unfounded accusations of wrongdoing.  

“As Trump drives more and more of his supporters to vote in person and away from vote-by-mail, it’s quite likely that we’ll see Trump getting many more votes on election night, the votes that are counted on Election Day,” Hasen said in an interview on “The Long Game,” a Yahoo News podcast.

“Then, four or five days later, [if] Biden becomes the winner as the absentee ballots are counted in Philadelphia or Detroit, that’s a recipe, if it’s close, for a really ugly election scenario,” he said.