In 2012 I posted a jokey running commentary on each general-election presidential debate. This time around I can’t muster the enthusiasm. Partly because social media has swallowed blogging whole, but mostly because there’s little fun in it when Donald Trump’s involved—you can’t parody someone who’s perpetually in self-parody mode. The reliably funny Alexandra Petri made a good effort, but her fake debate transcript isn’t much more ridiculous than the real one.

There’s really just one moment I want to comment on: Trump’s suggestion that the hack into the DNC’s systems could been done by “someone sitting on their bed that weighs 400 pounds.”

Yes, Trump displayed a notable ignorance about what cybersecurity is and who hackers are. And yes, he misplaced his modifier. (From my grammar-sensitive wife: “Tomorrow he’s going to say he meant the bed weighs 400 pounds.)

But what struck me was the gratuituous cruelty of his crack about weight. It sounded like the “400 pounds” phrase came at the end for a reason: Trump added it at the last second, an afterthought for bad measure. And it was startling to hear him so reflexively drop a line that’s not only cruel but also completely pointless.

Cruelty in political rhetoric, after all, is often calculated for effect. When Lloyd Bentsen insulted Dan Quayle in the 1988 VP debate, he was trying to make the younger senator look like a lightweight. It was a cheap shot—Quayle was right to say it was uncalled for—but at least it had a strategic purpose.

Trump wasn’t insulting a rival or a public figure or even a specific human. His larger point was that the hack might not have been done by a state at all. Even within the logic of his argument (such as it was), it’s not a relevant detail for the individual he posed as an alternative to be some kind of loner.

Yet Trump would like to point out that this theoretical person is fat, too. For Trump, cruel words are simply a default way of talking about people.

Often the people aren’t theoretical but real. In a post from earlier yesterday, Conor Friedersdorf compiles examples of Trump’s cruelty from over the years. Read together, they are stunning.

As Friedersdorf points out, harshness has its place in poltics. The problem isn't that Trump is an extreme example of a larger problem of American incivility or whatever, something solvable by way of taking a nicer tone. What Trump does is hateful and mean, and for its own sake. “This is vile behavior,” says Friedersdorf. Yes, it is—and Trump can’t even keep it in check for an hour and a half.