Zack Beauchamp for Vox:

The general sense among experts on American politics is that the nightmare scenarios — an outright stolen election, each party attempting to inaugurate a different president on January 20, or clashes between armed supporters of each side — are only plausible if the election is close, and even then, they remain unlikely.

“Unless there’s a catastrophic failure on Election Day … then the election only goes into overtime if the election is close enough to litigate in a state that is essential to the Electoral College outcome. That’s unlikely if the polls are even close to accurate,” Rick Hasen, a law professor at the University of California Irvine and author of the recent book Election Meltdown, tells me.

But Trump’s 2016 win and the emergence of a pandemic earlier this year were both “unlikely,” too. If we’ve learned anything from the past few years of politics, it’s that this kind of low-probability, high-impact event can happen — and needs to be planned for if the worst is to be avoided.

“In my mind, the worst-case scenario is the possibility of dueling inaugurations … a situation where we’re facing the end of the republic as we know,” says Franita Tolson, an election law expert at the University of Southern California.