lpetrich
Contributor
The Boston Globe collected the House election results for 2012, and I have worked out what the results are for proportional representation. I have recently calculated what would happen if larger fractions voted for the Democratic Party. The paired numbers are the number of Dem and Rep seats in the House that result. Nationwide and state-by-state are what the proportional representation is done over, and by party is the current single-member-district system. For doing proportional representation, the algorithm is the Hare system (round downward) followed by D'Hondt highest averages.
[table="class: grid"]
[tr]
[td]Tilt[/td]
[td]Dem%-50[/td]
[td]Nationwide[/td]
[td]State-by-state[/td]
[td]By party[/td]
[/tr]
[tr]
[td]0%[/td]
[td]0.46%[/td]
[td]220-215[/td]
[td]215-220[/td]
[td]201-234[/td]
[/tr]
[tr]
[td]1%[/td]
[td]1.41%[/td]
[td]224-211[/td]
[td]220-215[/td]
[td]206-229[/td]
[/tr]
[tr]
[td]2%[/td]
[td]2.36%[/td]
[td]228-207[/td]
[td]226-209[/td]
[td]212-223[/td]
[/tr]
[tr]
[td]3%[/td]
[td]3.31%[/td]
[td]232-203[/td]
[td]231-204[/td]
[td]214-221[/td]
[/tr]
[tr]
[td]4%[/td]
[td]4.25%[/td]
[td]236-199[/td]
[td]236-199[/td]
[td]222-213[/td]
[/tr]
[tr]
[td]5%[/td]
[td]5.20%[/td]
[td]240-195[/td]
[td]240-195[/td]
[td]231-204[/td]
[/tr]
[/table]
In the baseline case, D - R = 1%, and the Dems are down 5 seats in state-by-state PR, though up 5 seats in nationwide PR. They are down 33 seats in single-member districts (the current system).
For D - R = 2%, the Dems and the Reps are equal in state-by-state proportionality and for greater D - R, state-by-state proportionality approaches nationwide proportionality. But for D - R = 2%, the Dems are down 28 SMD seats.
For D - R = 7%, the Dems and Reps are equal in SMD seats, but the Dems would have 31 or 32 seats more with PR.
So I conclude that gerrymandering costs the Dems about 30 seats. The Reps might still hold the House after the upcoming elections, but it will be by a narrow margin, and their legitimacy will become more and more in question. I suspect that if the Dems win, they will have a narrow margin of victory.
The same is likely so in several state legislatures, and I think that if Democrats win in an uphill battle against gerrymandering, they ought to try to get rid of it.
[table="class: grid"]
[tr]
[td]Tilt[/td]
[td]Dem%-50[/td]
[td]Nationwide[/td]
[td]State-by-state[/td]
[td]By party[/td]
[/tr]
[tr]
[td]0%[/td]
[td]0.46%[/td]
[td]220-215[/td]
[td]215-220[/td]
[td]201-234[/td]
[/tr]
[tr]
[td]1%[/td]
[td]1.41%[/td]
[td]224-211[/td]
[td]220-215[/td]
[td]206-229[/td]
[/tr]
[tr]
[td]2%[/td]
[td]2.36%[/td]
[td]228-207[/td]
[td]226-209[/td]
[td]212-223[/td]
[/tr]
[tr]
[td]3%[/td]
[td]3.31%[/td]
[td]232-203[/td]
[td]231-204[/td]
[td]214-221[/td]
[/tr]
[tr]
[td]4%[/td]
[td]4.25%[/td]
[td]236-199[/td]
[td]236-199[/td]
[td]222-213[/td]
[/tr]
[tr]
[td]5%[/td]
[td]5.20%[/td]
[td]240-195[/td]
[td]240-195[/td]
[td]231-204[/td]
[/tr]
[/table]
In the baseline case, D - R = 1%, and the Dems are down 5 seats in state-by-state PR, though up 5 seats in nationwide PR. They are down 33 seats in single-member districts (the current system).
For D - R = 2%, the Dems and the Reps are equal in state-by-state proportionality and for greater D - R, state-by-state proportionality approaches nationwide proportionality. But for D - R = 2%, the Dems are down 28 SMD seats.
For D - R = 7%, the Dems and Reps are equal in SMD seats, but the Dems would have 31 or 32 seats more with PR.
So I conclude that gerrymandering costs the Dems about 30 seats. The Reps might still hold the House after the upcoming elections, but it will be by a narrow margin, and their legitimacy will become more and more in question. I suspect that if the Dems win, they will have a narrow margin of victory.
The same is likely so in several state legislatures, and I think that if Democrats win in an uphill battle against gerrymandering, they ought to try to get rid of it.