THE KRAUTHAMMER FALLACY.

THE KRAUTHAMMER FALLACY. I've been pushing back here quite a bit on the "Democrats won, but as conservatives" meme already, but a few reporters and other people have asked me to explain the riddle of how it can be that both congressional parties, as a result of last week's election, could actually have moved to the right. Here is Charles Krauthammer, for example, from Friday's Washington Post:

Democratic gains included the addition of many conservative Democrats, brilliantly recruited by Rep. Rahm Emanuel with classic Clintonian triangulation. Hence Heath Shuler of North Carolina, antiabortion, pro-gun, anti-tax -- and now a Democratic House member. The result is that both parties have moved to the Republican X = 55right.

Is that possible? Actually, yes. The simplest way to see that is to imagine a basket of watermelons with one cantaloupe in it, and a second basket full of peaches. Move the cantaloupe from the first basket to the second and, voila, the average per-fruit weight increases for both.

This mathematical reality does not, however, imply that the Congress as a whole has shifted to the right. Quite the contrary, in fact. To demonstrate the Krauthammer Fallacy as simply as I know how, let's assume that thepre-election ideological ratings of a simplified, 5-member Congress (with lower numbers being more liberal) look something like this:

Democrat A = 5
Democrat B = 15
Republican X = 55
Republican Y = 90
Republican Z = 95

Here the Republicans are the majority, their mean position is 80, and their median position is 90. The minority Democrats have a mean and median position of 10.

Next assume that in 2006 Republican X, who is a moderate by his party's standards (Charles Taylor, whom Shuler defeated, was ranked 90th most liberal out of 224 Republicans), is defeated by a Democrat who is a moderate by his party's standards (Shuler). Still, the new Democrat is clearly to the left of the ousted Republican: I do not hear anyone suggesting that a single Democrat won Tuesday by actually running to the right of his/her respective opponent.

Giving Krauthammer the benefit of the doubt, we'll assign this new Democrat an ideological rating of, say, 25 -- i.e., making him the single most conservative member of his caucus. The resulting Congress now looks like this:
Democrat A = 5
Democrat B = 15
Democrat C = 25
Republican Y = 90
Republican X = 95

Notice that the new Democratic majority has moved to the right: Its mean and median position are now 15, not 10. The same is true for the new Republican minority: Its mean and median both jump to 92.5. Still, the overall Congress has moved to the left -- and decidedly so.

The new majority's mean and median position of 15 are much different from the old majority's 80. The median and mean for the Congress as a whole has shifted, too: from 55 and 52 before the election, to 25 and 46 after.

Sorry, Charlie. Nice try.

--Tom Schaller