There are 80 precincts in the portion of Ada County lying in the 1st congressional district. Very roughly speaking, most of the city of Boise, and the areas to the east of it in the county, are in the 2nd district; again roughly, Cole Road, which runs north-sound through the center-west of Boise, is the dividing line between the districts.
That area in the 1st district is the part of Ada County generally voting Republican, in most places heavily so. It voted, for example, for John McCain over Barack Obama - decisively so. But it voted in the 1st District House race for Democrat Walt Minnick over incumbent Republican Bill Sali in numbers much higher - 31.7% higher, enough to give him a win of almost 5,000 votes in that part of Ada County; enough, in turn, to provide his winning margin. Even in the precincts Minnick lost decisively, he heavily outran Obama and other Democrats (generally 25-50% higher). These were people who did not vote for other Democrats, just this one.
Is there anything to be learned from these 80 precincts?
Maybe a little, and we'll start here. First point is that Minnick's win was spread around a bunch of the precincts, not concentrated in a few; he won 51 of the 80 precincts. So the simpler approach is to look at the precincts Sali won. Do those have points of commonality that make them stand out from the others?
Generally speaking, yes: Most of them are rural, among them the most rural and relately remote areas in Idaho's population-heaviest county. The precincts in the far north edge of the county, in the foothills north of Eagle and northwest of Boise (1, 2, 4) were substantial Sali wins. The precincts in the far southern reaches of the county (123, 125 for example) were substantial Sali win areas. The interstices between the cities - some of the areas between Eagle and Meridian, between Meridian and Nampa and between Meridian and Kuna - gave Sali good numbers. The rural area around Star did well for him. And, generally, his old state legislative district and home turf around Kuna stuck with him, delivering solid margins.
Minnick's margins? He won some rural precincts, but mainly he racked up numbers inside the larger growing cities: primarily Meridian, Eagle and western Boise. These have not been friendly areas for Democrats up to now, but they made a highly unusual exception this time.
The nature of that, in those specific precincts, ought to be research project #1 for Idaho Democrats over the next couple of years. Some of it may have to do with the specific dynamics of this race; maybe Sali, specifically, turned some of those people off. It could be that Minnick personally made a sale here; or it could be a combination of the two. It might be that this unusual voting pattern won't be replicated in 2010; or it could be a harbinger, a signal of opportunity to come for other Democrats. Whatever's the case, there's an important development here, maybe the most important single twist in the elections of 2008 in Idaho. That much we can say with some confidence, even without yet being sure exactly what it means.