As the GOP struggles with record-low polling numbers in the aftermath of the government shutdown, the media has begun handicapping the party’s chances in the 2014 midterm elections. In other words, how many seats could Republicans lose? Coming up against this are the effects of gerrymandering that altered the shape of many districts after the 2010 census. Redrawn lines have allowed the GOP to gain additional seats, more than should be expected based on the number of votes that went to the two parties.
In the chart below, you see every state with at least 7 seats in the House of Representatives. Each state is arranged based on the percentage of total two-party votes won by Republican candidates in that state compared with the percentage of Republican winners. The diagonal line represents how many seats Republicans should have won based on the total votes in each state. States above that line have more GOP seats than they should have, if there had been no gerrymandering.
In Pennsylvania, for example, 49 percent of votes between the two parties went to Republican candidates, but 72 percent of the winners were Republicans. According to the trendline, only 56 percent of the state’s delegation should be Republican. This 16 percent difference, out of 18 total seats, represents 2.9 additional GOP wins due to gerrymandering. If Republican support is still depressed a year from now, we could reasonably expect Pennsylvania to lose about 3 GOP seats. This is the state most at risk for a swing against the GOP.
Focusing on Pennsylvania, it’s very obvious to see in its specific voting records how gerrymandering worked. There were only 5 Democratic winners, but they all had blowout wins. The four biggest wins in the state were all by Democrats (69 percent or more), while the nine smallest wins were all by Republicans (59 percent or less).
Continuing this theme, we see the top five states with the highest potential for GOP losses. These five states add up to 10 congressional seats up for grabs. In all five states, there is a typical pattern of election results: very few wins by Democrats, generally in blowouts, but many wins by Republicans in close elections. In fact, the biggest wins in every state came from Democrats. The effect of gerrymandering has allowed for extremely solid Democratic districts, while spreading the Republican support thin. A drop of only 5 percent to 10 percent in GOP voter support could easily result in the 10 seats lost, as described above.
In these five states, the congressional breakdown is 51-21 in favor of Republicans, even though total votes casts were about even. Of these 21 Democrats, 20 of them saw wins with more than 60 percent of the vote. In case you were wondering if this is just a random occurrence, consider this: In all five of these states, both houses of the state legislature are controlled by Republicans. Yes, 10 out of 10 branches are GOP-controlled, and that’s why we see these skewed results.