From Josh Marshall:
"I don't think we can discuss this debate as citizens, take stock of it as a country, without noting that this is certainly the first time one candidate has openly threatened to jail the other candidate. Trump said openly that he would instruct the Justice Department to open a new investigation of Clinton and that he'd make sure it ended with her imprisonment. That's something we expect in kleptocracies and thin democracies where electoral defeat can mean exile, imprisonment, or death.
"Such a ferocious claim, one that puts our whole constitutional order on its head, is not something that can be easily undone. That's the ranting threat of a would-be strongman and dictator. The threat itself is like a bell that can't be un-rung. Through the course of what was often an ugly debate, I was thinking a lot of the destructiveness of this entire campaign, virtually all of which stems from Trump's transgressive, norm-demolishing behavior. It's a topic ... the country is going to need to wrestle with. None of this is going to disappear after November 8th. These are slashing wounds to the country's political fabric that will at best leave tremendous scar tissue we'll still see for decades."
UPDATE: Will Wilkinson of the libertarian Niskanen Center agrees.