Having spent only one day as House minority leader, Nancy Pelosi is already talking about the quick potential return of the Democratic party to the majority. While winning the minimum 25 seats required to regain the majority would be difficult, looking at the historic record, it is possible.
An examination of the past 30 congressional elections going all the way back to 1952, the average net partisan change in seats from one Congress to the next was just over 19 seats. Almost a third of those changes, 9 out of 30, had a net partisan swing of 25 seats or greater. Having a 25 seat swing, while larger than average, isn’t uncommon.
Of course, that level of swing goes to either party. If you go by just a crude look at averages and divide by two parties that would put the chances of Democrats regaining their majority at around 15 percent. A remote but not improbable outcome.
Just looking at an average swing over the past 50 years, however, is too simplistic. There are many other important factors that should be considered.
Republicans are likely going to benefit from the fact that in this decade they control more of the redistricting process, allowing them to design districts that are easier for their incumbents to hold, and so reducing the chance Democrats could win back control.
On the other hand, Democrats will benefit from what are, traditionally, the more liberal turnout demographics of a presidential election. In addition, last year saw the benefits of incumbency in House races reduced dramatically. If the pattern of incumbency no longer being such a large benefit continues, it will not necessarily mean Democrats will gain in 2012, but it does increase the possibility for big swings in seats springing from only modest swings in the public’s overall partisan support. On net, these general factors are probably a small plus for Democrats.
Whether Democrats gain or lose seats in 2012 will depend heavily on the state of the economy and politics in two years, but, looking at recent history, there is a decent possibility Democrats could win back control of the House. While I wouldn’t begin to guess this far out from an election what the results of that election will be, based on recent history, I would put the probability of Democrats winning back the House at roughly 15 to 30 percent.