New kid on the block

I'm adding a link to another new Montana blog, Dirt Between Light Bulbs, which appears to be interesting and well written. So I might as well go ahead and disagree with it right off the bat. Demosthenes argues that because Republicans won the popular vote for the Legislature 50-47, they should have been expected to win a 50-47 margin in the House (with three up for grabs).

T'aint so. If districts were perfectly apportioned, then the side that won just over 50 percent of the total vote (which Republicans did) would win 100 percent of the House seats. That detail matters if you are curious, as I am, about whether Democrats gerrymandered the districts before the next election. I don't dispute that Democrats tried to do it; I just wonder whether they succeeded.

It's a trickier calculation than you might at first suspect. Presumably, the purpose of gerrymandering is to create districts in which the votes of Democrats (in this case) are maximally effective while the votes of Republicans are discounted. So you try to construct districts in which Democrats win all the close races while Republicans win large victories in districts where a Republican win can't be avoided.

So did Democrats in fact win the close races while losing the lopsided ones? I actually spent a couple of hours trying to compute this for Yellowstone County in the last election, but it got too complicated, and I gave it up. To really nail it down, you would almost have to compute it on a precinct-by-precinct basis, comparing 2004 results to results from previous elections.

Even then, lots of things can go wrong. Plotting a strategy to win close races appears to be sound, but it can easily backfire. You can't afford to cut your margins too close. Did, for example, Carol Gibson lose her bid for re-election because Democrats got too clever for their own good? Hard to tell.

So did Democrats in fact successfully gerrymander the new election districts? I don't know, but I would sure like to see somebody come up with the answer.

UPDATE: For some reason, I can't link directly to the post. You'll have to scroll down to March 27.