Question arose in comments a couple of days ago which suggests something more than a quick reply: "I’d just be interested in any history you have on the chances of a challenger beating a weak incumbent in a rematch (as a Grant-Sali race would have been) versus a new candidate taking out the incumbent."
That had to do with a post on the 1st district U.S. House race, where the Democratic field shrunk from two candidates to one. The departed was Larry Grant, who ran against Republican Bill Sali two years ago and was hoping for a rematch. Still standing, and now the presumptive Democratic nominee, is Walt Minnick, who has not run for this office before but did run for U.S. Senate in 1996.
The question breaks into two parts, one having to do with beating incumbents, the other concerning whether rerunners might be better positioned to do it.
It's hard to get scientific about this because the data is pretty small - in most places around the country in recent years, and certainly in Idaho. The reality is that not many incumbents lose anymore, either in primary or general elections. Some do, as a number of Republican U.S. House members found out in 2006 (or Democrats in 1994). But it's unusual. (more…)