If we assume that nothing else affects House election outcomes but the partisanship of the districts—in other words, if we allow redistricting to have its maximum possible effect—we find that the 2011 redistricting cost Democrats 7 seats in 2012. This is not nothing, but it’s far less than what the Democrats needed to take back the House and about half what [election analyst Sam] Wang estimated.Read further, though, and a passage suggests that the presence of the constraint in the voting rights law that requires some fraction of the Congressional districts indeed is binding.
The effect is even smaller if we incorporate other important factors. Incumbency is the most important of these: lots of Republicans who were running as challengers or in open seats in 2010—and then won—ran as incumbents for the first time in 2012. We know that incumbency is a powerful factor in House elections, bringing candidates greater visibility, adding to their campaign coffers, and deterring quality challengers from running. On average, an incumbent in 2012 ran five percentage points ahead of a non-incumbent candidate from the same party in a similar seat. Sixty-one seats were were decided by less than this margin.
More important, once we took incumbency into account, the apparent effect of gerrymandering vanished. That is, the ability of Republicans to retain the House majority may have been due to incumbency advantage, not new and more favorable districts.
We went a step further and subtracted out our estimate of the incumbency advantage to simulate what 2012 would have looked like if this advantage had not existed. In this simulation, the Democrats won 219 seats—virtually eliminating the discrepancy between votes and seats in this election.
To be sure, separating out the effects of new districts and the effects of incumbency is not easy. The new district boundaries could also have factored into incumbency advantage—deterring potential opponents by making some districts more hostile territory in ways not captured by the district’s presidential vote. So we cannot conclude from this analysis that gerrymandering had no effect whatsoever.
Democrats never quite get a consistent advantage from the 1960s through the 1980s, as the symmetry measure suggests. There has been a Republican advantage since the mid-1990s, and the change in 2011, though favoring Republicans, was modest by historical standards.Yes, the current "partisan division" was present in the data years ago. Districts constrained to simple shapes are likely to violate the provisions of the Voting Rights Act, and Democrat politicians have prospered by appealing to constituencies allegedly protected by those provisions.
Why do Democrats have a somewhat chronic disadvantage in these graphs, especially in the last 20 years? Part of the reason is that Democratic votes are increasingly concentrated in urban areas where they are more likely to waste votes with large majorities. Jowei Chen and Jonathan Rodden have simulated thousands of redistricting plans in a handful of states and found Democrats generally do worse when districts are constrained to be compact (that is, as close to simple shapes like circles and squares as possible).
The editorial board of the Chicago Tribune erroneously blames gerrymandering but recognizes why safe districts for Members of Congress, specifically the younger Jesse Jackson, are not necessarily safe districts for constituents.
The Jacksons bought a cozy lifestyle with surplus money that, although supposedly isolated in campaign accounts, in fact was burning a hole in the congressman's pocket. The long-running and diabolical nature of their scheme suggests they felt entitled to do whatever they pleased with money that was all but unnecessary for Jackson's minimalist 2nd Congressional District campaigns.There's no incentive for such an incumbent to behave differently. Without the legions of desperate constituents to hold up as continued evidence of institutionalized oppression, such incumbents have a tougher time getting re-elected. The political integration of Congressional districts might be a necessary step toward the economic integration of communities. With spring break at hand, look for more on this point.
No, gerrymandering didn't drive the ex-congressman to a life of crime. Gerrymandering did, though, enable it. With no viable opposition, he had little need to buy expensive TV time — and, to be frank, he had fewer pesky journalists going line by line through his campaign finance reports. More scrutiny might have detected questionable spending patterns.
The corrupt if legal packing of congressional (and state legislative) districts to make them safe for either major party is an Illinois problem and a national problem. The political research website Ballotpedia reports that only 14.5 percent of all U.S. House races, or 63 of 435, were decided by 10 percentage points or less in 2012: The average Democratic victory margin was 35.7 percent; the Republican average was 28.6 percent.
Think about those huge margins of insulation. Think too about how voters in only one of every seven districts got to choose their U.S. representatives in genuinely competitive races. Why? Because pols in Illinois and many other states rigged the majority of races to all but guarantee victory to one party or the other. Often the candidates don't even matter, just the D or R after their names.
And on goes the protection game. Voters in the new district drawn to insulate Jackson are less than a week from learning who likely will replace him. Whichever Democrat emerges from the Tuesday special primary is a heavy favorite to win the April 9 general election.
That Democratic victor may never have to face serious competition again — at least until the next redistricting after the 2020 federal census. He or she will live out this decade with a tremendous advantage: a district drawn by one party, to benefit one party.
Not that an incumbent blessed by gerrymandering can't find ways to squander a nearly sure thing.