There is much to debate about liberal economist and New York Times writer Paul Krugman, but here are two facts that seem hard to argue with:

Krugman is a very smart economist.

Krugman’s debate style is uncivil and uncharitable.

When Krugman disagrees with people, he calls them names. If Krugman dislikes your policy proposals, and you make a mistake in your work, he is utterly unforgiving, uncharitable, and dismissive. And if you broadly align against Krugman on ideology, he’ll suggest your side is responsible for murder, he won’t read you, and then, in his trademark move of projection, he’ll call your side close-minded.

Here’s what baffles me about Krugman’s apparent antipathy towards those who disagree: Krugman himself is open-minded enough to change his mind on many issues (i.e., Krugman in 2003, “I’m terrified about what will happen to interest rates once financial markets wake up to the implications of skyrocketing budget deficits”). A guy who can hold two different positions over the course of time ought to realize that those holding differing opinions might not all be fools or liars.

But here’s the thing — I bet Krugman does realize he’s not simply arguing against fools and liars. After all, he’s smart.

I suspect Krugman’s incivility is a deliberate strategy. And this passage from an old Krugman post is why I think so [emphasis Krugman's]:

I’m not saying to turn the other cheek and always say something polite as a general principle; by all means lash out at your critics, if you have something to gain by doing so. Rudeness at the proper moment can serve a purpose — as I hope I’ve demonstrated over the years. But if you vent for the sake of venting; if you alienate people you’re going to need; then you’re just being stupid.

So, when you see Krugman pinning murder on Tea Partiers, or getting nasty, don’t ask yourself, “Why can’t he argue like an adult?” Ask yourself, “Why is he choosing not to argue like an adult?”