If you want to know why the congressional debt reduction commission failed so miserably, one reason (among many) is clearly visible in Arizona, where Gov. Jan Brewer is trying to torpedo one of the few efforts anywhere in the country that might modulate the holy war now ravaging Capitol Hill.

Eleven years ago, in a spasm of good sense, the voters of Arizona decided that politicians should no longer control the boundaries for legislative and congressional districts. Instead, they gave that power to a five-member commission composed of two Democrats, two Republicans and an independent chairman.

The innovation was important for two reasons. First, politicians always draw lines that protect themselves and their parties, while depriving most citizens of any real choice in who represents them. They even admit their goal is to pick their voters instead of having the voters pick them. And second, lawmakers from safe districts have little incentive to listen to, or work with, members from the other party. In fact, their only real fear is a primary challenge from a rival accusing them of insufficient orthodoxy.