Monday, November 14, 2011

The Relative Strength of Congressional Incumbents

How applicable are Obama-McCain numbers to local congressional races? I compared how Obama did in each congressional district to how the incumbent Democrat did and McCain to how the incumbent Republican did. For open seat races, I compared the Democrat to Obama.

I excluded districts where a candidate ran unopposed and those that were significantly one-sided either way. The incumbent will win these races whether he performs above or below the Presidential candidate.


Incumbents average a lot better than their Presidential candidate. A rule of thumb is that incumbency is worth 3 points, but these numbers suggest it may be larger. The Democrats had a higher average, but this may be explained by the quality of Democratic challengers vs. Republican challengers. In some cases Republicans barely contested the seat. There were also a number of Democrats in southern legacy districts who continued winning even as their district started voting Republican at a Presidential level. Some of these congressmen didn’t survive the 2010 Republican onslaught, while others are retiring this year. You can see this in the list of Democrats who did the best compared to Obama. Many who did the worst compared to Obama also lost in 2010.


The Republican performances weren’t nearly as strong as the Democratic ones. While fewer Republicans who had strong performances will run in 2012, there are also several Republicans who ran further behind McCain than the Democrats ran behind Obama.


While there are several factors into how an incumbent performs, including the quality of the challenger, incumbents in a number of states performed similarly. I’ve highlighted those where one party’s incumbents did significantly better compared to Obama than Republican ones did compared to McCain. And vice-versa. I’ve highlighted those in yellow.


There were ten states where the Democratic incumbents ran significantly more ahead of Obama than the Republican incumbents did ahead of McCain. Of these, however, six are southern states where Democratic congressmen still manage to hold districts that vote Republicans on the Presidential level.

That’d explain the relative Democratic strength and Republican weakness in Georgia, Kentucky, North Carolina, South Carolina, Tennessee, and Texas. Keep this in mind when anticipating whether the GOP can pick up districts in these states. Fortunately, Republicans picked up a number of them in 2010. In 2012, North Carolina won’t be as easy as some people think it will.

It’s not surprising that Arizona Democrats ran far ahead of Obama, while Republican incumbents didn’t run far ahead of John McCain.
Knowing this, Democratic congressmen in them will once again be difficult to defeat in each of them.

The weak performance of Colorado Republicans is worrisome since the GOP has several potentially vulnerable incumbents. I’m surprised at the incumbents’ relative strength compared to Obama in Indiana, Minnesota, and Missouri, since Obama did very well in each of those states. Ohio Democratic incumbents did well enough to outweigh Dennis Kucinich, who has trouble appealing to anyone outside his base. Put Kucinich in anything close to an even district and he’ll lose.

The good news on the Republican side is the party’s strength, and Democratic weaknesses, in Iowa. There is a lot of opportunity there, especially if Obama is lackluster. California, Florida, Illinois, Michigan, New York, Ohio, Wisconsin, and Pennsylvania all have vulnerable Republicans. Fortunately, Republicans have run very strong in these states.

On the other hand, low R+ PVIs in Texas could result in losses. If a court draws the map, Republicans there might be in trouble.

There were other states where neither Republicans or Democrats didn't have two incumbents. That makes any relative comparison of the two parties difficult, although one can see why Democrats lost both New Hampshire districts in 2010.


Incumbents are difficult to beat in a non-wave year. Most will be tough to beat, but those that aren't as strong will be vulnerable.

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