A fair question, and there's a very good answer:

 

First, I have to acknowledge that there are no absolutes in politics. A candidate who wins one year and sees his or her support level drop by 30 or 40 percent the next election is going to lose -- no gerrymander can save him/her. But creative line-drawing can protect a candidate from a swing of 10 or even 15 percent -- or draw an incumbent out of office even when support levels remain the same.

 

The key is recognizing that there are two kinds of gerrymanders: partisan gerrymanders, and bipartisan (incumbent-protection) gerrymanders. [Leaving aside racial gerrymanders for another discussion.]

 

A. Bipartisan gerrymanders ensure the safety of all (or almost all) incumbents on both sides of the aisle. California's 2001 plan is perhaps the ultimate example of this. California's 53 Congressional districts held 212 elections in 2002, 2004, 2006 and 2008. A total of ONE incumbent lost his/her general election. When incumbents retired, the incumbent's party held the district in every case. That's one loss in 212 elections, despite the unusually large Democratic surges in 2006 and 2008. California's incumbent-protection gerrymander provided a sea wall of protection against the Democratic waves in 2006 and 2008.

 

B. Partisan gerrymanders attempt to do two things: (1) draw as many safe districts for the party in control as possible; (2) where a district cannot be drawn completely safe for the party in control, at least make it competitive so that the minority party has as few safe districts as possible. Florida and Pennsylvania are good examples of one-party gerrymanders.

 

C. The third type of line-drawing occurs in states where neither party controls the process (so there's no partisan gerrymander) but tradition / local rules / whatever limit the extent of the incumbent-protection gerrymandering that the legislature feels it can justify. Iowa is a good example of this but there are others.

 

I haven't reviewed the list of seats that have changed parties this decade, but I think if one does so one will find that they are disproportionately from states in categories B and C, and that the states in group A (such as California) have seen essentially no change in their partisan split -- despite the massive swings in voter opinion between 2002, 2004, 2006, 2008, and this year.

 

That's probably more info than anyone wanted, but here's the key distinction: bipartisan gerrymanders protect everyone; partisan gerrymanders often draw some competitive districts by design. Both types intentionally use the power of the map to subvert the voters' ability to effect change when the voters wish to do so.

 

- Doug

 

Douglas Johnson

Fellow

Rose Institute of State and Local Government

Claremont McKenna College

o 909-621-8159

m 310-200-2058

douglas.johnson@cmc.edu

www.RoseReport.org