MARVELING over a presidential candidate’s arrogance is like noting that a hockey player wears skates. It states not just the obvious but the necessary. You can’t zip across the ice in Crocs, and you can’t thrash your way to 1600 Pennsylvania Avenue if your confidence doesn’t bleed into something gaudier. Arrogance is the grist, and arrogance is the given.

But what flavor? And what measure?

That’s where candidates — and the presidents that some of them become — differ, in ways that shape the sorts of messes they’re likely to make. And that’s where Newt Gingrich provokes real concern. You have to take another politician’s ego, double it, and add cheese and a side of fries to get to Gingrich. An especially heaping, unhealthy diet of self-regard slogs through his veins.

His 1990s nemesis Bill Clinton had (and surely still has) no small amount of his own vanity, and it lay largely in his conviction that his charm and cunning enabled him to wriggle out of jams and get away with indulgences that would doom a lesser mortal. He fancied himself an escape artist extraordinaire.

That partly explains the risk he took with Monica Lewinsky, along with his verbal gymnastics upon the discovery of the affair. The scandal’s diminution of his presidency was the price he and we paid for his particular arrogance.