Bye-Bye, Bayh – But Why? Explaining Senate Retirements Before 2010

Why did Indiana Democrat Senator Evan Bayh decide not to seek reelection, and does it foreshadow a coming Republican wave in the 2010 midterm elections? In Bayh’s case, it is not clear that his decision was driven by a sense that he was electorally vulnerable; although he potentially faced a strong opposition candidate, his poll numbers were strong and he had raised plenty of money. Rather than electoral considerations, Bayh said he was stepping down because he could no longer tolerate the partisan bickering and policy gridlock in the Senate.

Skeptics, however, suggest that Bayh’s decision was motivated more by fear of the coming Republican electoral wave in 2010 than by any dissatisfaction with life in the Senate.  Political scientists have long argued that members of Congress (MC’s) act strategically when it comes to running for office, with more incumbents tending to forego a reelection run when they calculate that they are most vulnerable to defeat.  The decision not to run often reflects the realization that vulnerable incumbents tend to attract the strongest – that is, the most experienced and well funded – challengers.  And Bayh, by my unofficial count, is the 10th incumbent Senator who has decided not to seek reelection.  Is that an unusually high number? And, if so, what if anything does it tell us about 2010?

In fact, it is an unusually high number of retirements. Keeping in mind that in a typical election cycle, 33 or 34 Senate races are contested, the table below shows the average number of Senators who seek reelection during the last five decades (I don’t include data for the most recent decade) and the results:

Decade Number Seeking Reelection Lost Primary Lost General Election Percent Elected
1950’s 30 1 6 77.3%
1960’s 32 2 4 80.8%
1970’s 27 2 6 67.7%
1980’s 29 0 3 88.0%
1990’s 26 0 3 87.4%
50-year average 27 1 3 85.2%

On average, then, the number of Senate incumbents across five decades from 1950 through 2000 who do not seek reelection is about six.  Already, almost twice that number have announced that they will not run in 2010.  Also consistent with the strategic politician theory, we see that reelection rates go up in years when fewer incumbents run, which supports the notion that the weaker incumbents are choosing not to run when they are most vulnerable to defeat.

Of course, these are averages. It might be more revealing to look at specific “wave” years, such as 1994, when Republicans swept into power in both the Senate and the House for the first time in four decades.  Was that election preceded by an unusually high number of Senate retirements?   Here’s the Senate data for 1992-1996:

Year Number Seeking Reelection Lost Primary Lost General Election Percent Elected
1992 28 1 2 82%
1994 26 0 1 92%
1996 21 1 3 90%

So we see that in the two election cycles, 1992 and 1994, in which you might think Senators acted strategically, retirement rates were about par for the course.  Interestingly, it was after the Republican takeover that we see a huge jump, to 12 in 1996, in the number of Senators not seeking reelection.  One explanation for this may be that Democratic Senators no longer wanted to serve in a chamber dominated by the opposition party.  This may in part have been a reaction, much like Bayh’s, to a more partisan political environment more than to electoral vulnerability.

One way to untangle what’s happening in the current cycle is to look more closely at which Senators are stepping down.  According to the GreenPapers website, there are 34 Senate seats up for election in 2010, with 18 currently held by Republicans and 16 by Democrats. Here’s the partisan breakdown of the 10 that I have identified who to date have announced that they are not running for reelection:


Bayh (IN)

Burris (IL)

Dodd (CT)

Dorgan (ND)


Bond (MO)

Brownback (KS)

Bunning (KY)

Gregg (NH)

LeMieux (FL)

Voinovich (OH)

Rather than a majority of vulnerable Democrats, we see that most of the incumbents choosing not to run are Republicans.  Among the four Democrats, it is true that three faced tough reelection battles with both Dodd and Burris especially vulnerable. But what about the Republicans? Bunning was certainly vulnerable. LeMieux was a placeholder, appointed by Governor Crist with no expectation that he would run again. But what about the other four?  All would likely have won reelection, although some, like Gregg, faced the likelihood of strong opposition.  Brownback is running for Governor. Both Bond and Voinovich are getting up in years and wanted to spend time with family.

Of far more interest, I think, is their Senate voting record. Based on the latest Senate ideological rankings by Simon Jackman here, Bayh was the second most moderate Democrat in the Senate and Dorgan the 11th.  Voinovich was the 3rd most moderate  Republican, Bond the 5th most, Gregg the 10th and Brownback – who is running for another office – the 18th.

In short, what we see here is that most of the retirements that don’t seem driven by electoral considerations are by members who are from the more moderate wings of the two parties. It is possible, of course, that they would have faced primary challengers from their ideological flanks on the far Left and Right.  But the data is also consistent with the story that Bayh tells when explaining his decision not to seek reelection: that in an increasingly polarized Senate, those in the middle who seek moderate policies and bipartisanship are feeling increasingly frustrated and isolated.  By choosing not to run, of course, they make it possible that they will be replaced by more ideologically extreme Senators, thus widening the current Senate divide between Democrats and Republicans.  But apparently this is not enough to persuade them to run again.

The bottom line?  Senators are strategic.  But sometimes that strategy turns more on policy considerations than on electoral ones.   Yes, they are continually calculating whether they can win reelection.  But as Richard Fenno argued long ago, Senators also want to govern, by passing bills that achieve their goals.  Apparently that is becoming harder to do for Senate moderates in both parties.

If I get a chance, I’ll run the House numbers.

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