I've generally thought that the current state of redistricting skews the balance between Democrats and Republicans in the House of Representatives. But how much and in whose favor? And how do we measure?
To get an "expected" value, I took the 2008 vote totals (from The Green Papers) for each House race and totaled them by state. Given those totals, how many Democrats and how many Republicans would be elected from each state if statewide proportional voting were used? And then how many do we actually have? Also, I looked at, for each state, the average victory margin for Democrats and Republicans.
| State | # CDs | Expected # Dems | Expected # Reps | Actual # Dems | Actual # Reps | Avg Dem Victory Margin | Avg Rep Victory Margin |
| CA | 53 | 32.8 | 20.2 | 34 | 19 | 0.55 | 0.22 |
| FL | 25 | 12.1 | 12.9 | 10 | 15 | 0.41 | 0.22 |
| GA | 13 | 6.6 | 6.4 | 6 | 7 | 0.45 | 0.33 |
| IL | 19 | 11.7 | 7.3 | 12 | 7 | 0.54 | 0.20 |
| MA | 10 | 8.8 | 1.2 | 10 | 0 | 0.63 | -- |
| MI | 15 | 8.2 | 6.8 | 8 | 7 | 0.40 | 0.23 |
| NC | 13 | 7.2 | 5.8 | 8 | 5 | 0.34 | 0.25 |
| NJ | 13 | 7.4 | 5.6 | 8 | 5 | 0.41 | 0.20 |
| NY | 29 | 19.6 | 9.4 | 26 | 3 | 0.48 | 0.25 |
| OH | 18 | 9.4 | 8.6 | 10 | 8 | 0.29 | 0.22 |
| PA | 19 | 10.6 | 8.4 | 12 | 7 | 0.31 | 0.21 |
| TX | 32 | 13.3 | 18.7 | 12 | 20 | 0.44 | 0.42 |
| VA | 11 | 5.9 | 5.1 | 6 | 5 | 0.34 | 0.21 |
The table shows all states with at least 10 House seats. What's interesting is that the actuals for all of the states except Florida and New York are within 1 of the expected, using the "proportional voting" measure.
Now, about the methodology, this is admittedly a crude measure, because people often vote for individuals and may vote a different party if the individuals change. Also, a number of states had races with no opposing Democrat or Republican: California had 6 Dems and 2 Reps who had no opposition from the other major party; Texas had 2 Dems and 6 Reps unopposed; Florida, Georgia, New York and Virginia each had 2 Dems unopposed; Illinois, Michigan, New Jersey and Pennsylvania each had 1 Dem unopposed; and Massachusetts had 6 out 10 Democrats unopposed by Republicans!!! These races can obviously skew the results. (Note: Florida reported no vote totals for the 2 unopposed races, so I counted them as 100,000 votes for the winning Dem.)
I've included in the table the average margin of victory for Dems and Reps in each state. To compensate for races where a party faced no opposition from the other major party, I capped the margin at 75 points. Most states races with candidates from both parties did not show margins greater than 75 points. However, New York was an exception, where CDs 10, 11, 12, 15 and 16 all had greater margins (88, 87, 80, 84 and 93 points, respectively). The interesting thing to note is that in every one of these states, the Democrat's average margin of victory was greater than the Republican's. This would indicate that, overall, gerrymandering is still favoring Republicans.
Looking at individual states, it jumps out to me that Florida is most egregious in favoring either party, and the favored party is the Republicans. By the total vote count, we would expect a split of 12D-13R, but we have 10D-15R. In addition the Democrats average margin of victory is 41 points, while the Republicans is 21 points. As mentioned above, 2 Democrats ran unopposed, so we counted their margins as 75 points, but the other 8 Democrats had Republican opponents. Of those 8, 4 won by 40 points or more (40, 43, 55 and 64, respectively). The others won by 4, 9, 16 and 24 points, respectively. For the Republicans, 11 of 15 races were decided by 25 points or less, and only 1 of those was less than 10 points (FL-25), so most of their wins were in that comfortable, but not wasteful 10-25 point range. Efficient. (Here's the district map.)
New York is interesting because by the total vote count measure, it would seem to favor Democrats pretty heavily. Yet, the average margin of victory for Democrats was 48 points, to the Republicans 25 points. As I noted above, in 5 seats, all in the NYC area, Democrats beat Republicans by more than 75 points. In 2 other seats, no Republican ran (which we counted as 75 point wins). Democrats won the 2 closest races (NY-29 by 2 points and NY-24 by 4 points). Both of those districts have traditionally been Republican, as has NY-20, which Kirsten Gillibrand won by 24 points. So Democrats won 3 traditionally Republican seats fair and square (i.e. by running great candidates). It's hard to see how districts could be drawn upstate to be more fair and still favor more Republicans. (See the map here.) One could make districts 26 thru 29 more compact, but Democrats won those NY-27 and NY-28 by 53 and 56 points, respectively, some the modifications would more likely make NY-29 safer for Democrats and give them a better shot at NY-26. I would also argue that NY-25, NY-22 and NY-19 are districts Republican should have a legitimate shot at, but they have not done well there in the last 2 cycles.
Downstate it's hard to find a way to give Republicans more seats without serious gerrymandering. Of course, they only just this cycle lost NY-13, but they lost it by 29 points in an open seat race. They have some significant voter concentrations out on Long Island, but they lost NY-1 and NY-2 by 17 and 34 points respectively. They won NY-3 (Peter King) by 28 points, but when King moves on, we would expect a much closer race (i.e. not necessarily Republican votes to spare). Except for NY-1 and NY-3 on Long Island and NY-19, which stretches from north Westchester County up to Poughkeepsie, Republicans could not muster 100,000 votes or a closer margin than 28 points in any downstate district. Thus, "fairer" districts would not legitimately give them more seats. Republicans got about 2 million House votes in New York, to the Democrats 4.2 million, But upstate Republican votes are fairly spread out among the districts. They lost the 2 closest races and have competed poorly in traditionally Republican districts update. The best conclusion for New York is that gerrymandering is not costing them seats. They simply have failed to compete effectively (or one might say, have turned voters off) in the last couple of cycles.
California: given the total vote count, it seems pretty much in line with what's expected. But look at the average margin of victory (Dems 55 points, Reps 22 points) and it looks like Democrats should expect more seats. Overall the state is very good at incumbent preservation. Out of the 53 seats only 7 had victory margins of 15 points or less, and of those Republicans won 6 of them. Two of those 7 are in the northeast (CA-3 and CA-4), 1 near the Bay area (CA-11), and the rest in southern California (districts 26, 44, 46 and 50). (See the map here.) To me the Republicans should have nothing to complain about. Perhaps they could take CA-47 if it were carved different, but CA-46 next door is carved for them. Down in San Diego, CA-53 is strongly Democratic, but making it more compact could make CA-50 more competitive. Also, more aggressive Democratic district-making would threaten Republican's CA-52 by swapping some areas of it with CA-51. California districting does not look like it's unfair to Republicans.
And what about Texas? Looking at the total vote count, the split is close to what you would expect. Interestingly, the average victory margin for Republicans is pretty close to that for Democrats (44 points vs. 42 points). Like California, there are few competitive seats. Only 6 out of 32 hard victory margins of 15 points or less. Democrats won 2 of those (TX-17 by 8 points, TX-23 by 14 points). The Republican wins were in districts 7, 10, 22 and 24 by 14, 11, 7 and 15 points, respectively. Even though Democrats lost 5 seats after the 2003 Tom Delay honorary gerrymandering, it's hard to see how Democrats can make significant gains through more compact redistricting, although 1 or 2 seats would be possible. Of course, as noted previously, Texas will probably get 4 more seats, and the population increase is 2/3 Hispoanic. And one last note: what's the deal with TX-29? The total vote count was barely over 100,000 whereas most other districts had close to 200,000 voters. (Here's the map.)
Looking at the rest of the large states, the number of Democrats vs. Republicans is fairly in line with expectations. In Pennsylvania, Ohio and North Carolina, Democrats should not expect more from fairer districts. In all 3 states there are slightly more Dems than the total vote count would predict and the difference in victory margin between Democrats and Republicans is less than 10 points. In Georgia, Michigan, New Jersey, Virginia and Illinois, Democrats possibly could get an extra district in each thru fairer districts, but I have not studied the maps in those states. In those states the differences in victory margin are 12, 17, 21, 13 and 34 points, respectively.
In summary, in the largest states we see lots of safe districts for both parties; no surprise there. Overall the balance between Democrats and Republicans is not far from what we would expect if we had proportional voting. But looking at the difference in victory margins, Democrats could expect to get a handful of additional seats if districts were fairer.
Thanks for reading.
