Senate vs. House politics

Not long ago I shared a platform with a colleague who, in a valiant attempt to improve Democratic morale, recalled that even though unemployment was over 10 percent in 1982, mortgage interest rates stood at 14 percent and Ronald Reagan’s approval rating fell below 45 percent, his party did not lose a single Senate seat in that year’s midterm. The lesson, my fellow panelist averred, was that with the right message, losses could be averted — that whether we faced a 1982 or a 1994 was in our hands. 

That hopeful historical tale conveniently omitted the fact that Republicans did lose 26 House seats that year. However, the different result in the two bodies underlines the fact that the dynamics in the House and the Senate are not always exactly the same. Since World War II, the party occupying the White House has lost House seats in 14 of 16 midterms, with an average loss of around 23 seats. By contrast, the in-party has lost an average of four Senate seats in 11 of 16 midterms. In 1962, John F. Kennedy lost four House seats while picking up three in the Senate. In 1970, when Richard Nixon was losing 12 seats in the House, the GOP added two to its Senate total. And, of course, the results were different in 1982.

A more restricted sampling — a president’s first midterm — suggests an even wider disparity between the chambers. In the House, presidential parties lost seats in eight of nine first midterms, giving up an average of 19 seats.

By contrast, in this same set of elections, the president’s party actually gained Senate seats in four of nine first midterms. The average change was a loss of fewer than two seats.

The differential is intriguing because, whatever the year, House and Senate elections take place within the same political climate. The president’s popularity, the economy and the national mood are the same for both sets of races.

Why the seemingly different dynamic?

Of course, in any given year, there is a small number of Senate races, and their idiosyncrasies loom large in any average. Those unique qualities wash out in the 435 House races waged each cycle.

The two bodies are also on different calendars. House members running in a first midterm came in with the sitting president, while senators running for reelection did not.

Beyond that, open seats fuel much of the change in both chambers and retirements are not always proportional in the two bodies.

Additionally, Senate campaigns often generate more media interest and more advertising than House races, and thus senators can be better known than their House counterparts. Their strong personal images, positive or negative, help them stand apart from the ebb and flow of events. Lesser-known House members are more likely to be swept in or out with the national tide.

Exposure provides another structural difference. Statistical analysis demonstrates that the number of seats a party is defending has a much more profound impact on Senate elections than on the House (for reasons beyond the scope of this piece). Indeed, the analyses reveal that for every seat the party in power has to defend, it loses about eight-tenths of a seat.

That takes us back to my colleague and the 1982-2010 comparison. In 1982, Republicans, the White House party, were defending 13 Senate seats. This year Democrats are defending 18 seats. Thus, on the basis of exposure alone, one would expect Democrats to lose four more seats than Republicans did in 1982 (.8 x 5 = 4).

If only the scale of Democratic Senate losses were dictated by message choices alone. Alas, structural dynamics will almost certainly produce some Democratic losses in both chambers.

Mellman is president of The Mellman Group and has worked for Democratic candidates and causes since 1982. Current clients include the majority leaders of both the House and Senate.