Earlier this week, Paul Krugman wrote of a “wonk gap” between Republicans and “conservative ‘experts,’” and their political and philosophical counterparts. Writes Krugman, “the G.O.P. [has a] near-complete lack of expertise on anything substantive.” Or, put in its elementary school playground debate formulation, he says, “You guys are just stupid.”

It’s tempting to dismiss the column as just Krugman being Krugman. But he illustrates a gap that is real, important and truly worrisome: the gap in thoughtful discourse between different viewpoints in American politics. Discourse is vital both because it forces those viewpoints to sharpen their better arguments while discarding their weaker ones, and because it moves policymakers and the public toward better decisions. However, instead of seriously and thoughtfully engaging in such conversation, too many politicians and commentators give serious attention only to ideas and arguments in line with their own views.

Sadly, Krugman occupies one of the most echo-ey of those chambers, routinely misunderstanding (and then lampooning) viewpoints at odds with his own. (For some examples, see this by Tyler Cowen, or these posts by Alan Reynolds.) Indeed, if Krugman followed thoughtful policy discourse, he would not have buttressed his “wonk gap” column with three highly dubious arguments:

• Because the public is skeptical of defunding the Patient Protection and Affordable Care Act (aka Obamacare), PPACA is not unpopular.
• The moderation of health care spending is due in part to the Affordable Care Act.
• Because government employment has declined in recent years, there has not been a large increase in the size and growth of the federal government under Barack Obama. (Never mind more relevant measures of government size and growth, such as expenditures, debt, legislative reach, regulatory scope, and intervention in private affairs.)

Krugman, of course, isn’t the only commentator or politician to shelter himself in an echo chamber. It’s too easy to become a public-policy Stuart Smalley, believing, “My ideas are good enough, smart enough, and doggone it, people like them (and my opponents are just stupid).” But that deprives America of important political considerations and better public policies. And that truly is stupid.