Such may well be the case with the common explanation for the decline in the number of competitive congressional districts.
Many political observers are certain that, during redistricting, state legislatures carefully carve "designer districts" to ensure that one party always wins it. But the problem isn't just that very, very few House incumbents lose: It's that very few even have competitive races. In 2002, only three dozen incumbents won by 10 percentage points or less. In 2004, fewer than two dozen won that narrowly. The endangered House member is a rarity.
Three political scientists from Emory University contend that redistricting is not the chief culprit. Alan Abramowitiz, Brad Alexander, and Matthew Gunning argue that the nation's increased partisan polarization, combined with the advantages of incumbency, have resulted in fewer strong challengers running in districts that ought to be competitive.
Consider that 394 of the 401 members who sought re-election in November won. Of the seven who lost, four were Texas Democrats targeted for defeat by their state's Legislature during a controversial, mid-decade round of redistricting. (Two of them lost to Republican incumbents.) Only three losing incumbents were from outside the Lone Star State: freshman Max Burns, R-Ga., and veterans Phil Crane, R-Ill., and Baron Hill, D-Ind. In 2002, only eight incumbents lost, and four were in dual-incumbent matchups.
Vital Statistics on Congress reported that the re-election rate for House members, which averaged just under 92 percent during the 1950s, '60s, and '70s, jumped to 95.5 percent in the '80s, then slid a bit to 93.7 percent in the '90s. In the past three elections, the re-election rate has averaged 98 percent.
In comparing House and presidential results, Abramowitz and his colleagues found that from the 1950s to the '80s, the number of marginal House districts (ones that a presidential nominee won by 5 points or less) exceeded the number of safe seats (districts where the winning House candidate's margin was at least 10 points). But from 1992 to 2000, the number of safe seats exceeded the number of marginal seats. In 2002 and 2004, that trend became even more dramatic.
If redistricting were the prime cause of the lack of competitive House races, Abramowitz, Alexander, and Gunning argue, the number of safe seats would rise immediately after redistricting. Yet they've found that "redistricting did not cause a substantial increase in the number of safe districts or a substantial decrease in the number of marginal districts in 1982, 1992, or 2002."
The Emory political scientists maintain that increased polarization along partisan and ideological lines is more responsible for the lack of competitive districts. They say that, as a result of "powerful social forces at work in American society, including internal migration, immigration, and ideological realignment within the electorate," Democratic districts are getting more Democratic and Republican districts are growing more Republican.
On the ideological side, they suggest that Stanford University's Matthew Levendusky was correct when he substituted "sorting" for "polarization," meaning that voters are bringing their policy and partisan preferences into alignment. Conservative Democrats, many of whom are in the South, are increasingly voting Republican, while liberal Republicans, many of whom are in the Northeast, are increasingly voting Democratic.
The Emory scholars also note that House members have learned to take full advantage of the official resources of their office and to maximize their spending advantages. Most incumbents have simply become unbeatable.
The decline in competitiveness appears to be a continuous process, not just one that takes place immediately after redistricting. Fewer voters are splitting their tickets. Fewer capable challengers are stepping forward. And when they do, they tend to get overwhelmed by the incumbent's financial resources. The result of all of this is a far more polarized House, one with fewer members inclined or politically able to work for legislative compromises.