With regard to gerrymandering helping the Democrats:
Single-member geographic districts (districts that are most prone to gerrymandering) have a funny effect on party strength.
Such districts HELP:
- Small parties that are geographically compact (e.g. Canadian Bloc Quebeqois)
- Large parties that are geographically expansive (e.g. Canadian Liberals, American GOP)
These district HURT:
- Small & medium parties that are geographically expansive (e.g. Canadian NDP, British LibDems)
- Large parties that are geographically compact (e.g. American Dems)
Gerrymandering is hurting the Democrats now, but helped them through the 1980's...for two reasons. First, the Democrats controlled most of the state legislatures, especially in the South, until the 1990's. But more importantly, the Democrats have become more geographically compact while the GOP has become more geographically expansive.
The Dems have lost strength in rural areas and gained stregth in cities. This has made it easy for the GOP to draw a few districts with huge Democratic majorities, leaving the majority of districts with a moderate Republican lean. As an example, Al Gore got 80% of the vote in about 20 CDs in 2000...Bush didn't get 80% of the vote in a single district, but won more districts overall.
An execellent and concise analysis of single-member-district polictics.
On Beef's post: I think a Presidential result would be less likely to come down to the wire. The total number of swing CD's right now are less than 50. The number of swing state EV's are much more than 50. So at the big picture level the race is easier to project at the CD level than at the state level.
Also, the chance that a very close vote in one district will change the outcome is greatly reduced. For a close vote in FL to change the result, the candidates must now be within 27 EV of 270. If the vote uses the ME/NE system a close state only matters if the candidate is within 2 EV of 270. So, by that measure the chance that a close result changes the election is also reduced.