From David Kaiser's History Unfolding blog, a fascinating look at the effects of gerrymandering on Congressional elections:
In 2004, the Republicans won 232 seats with 51.4% of the major party vote; in 2006 the Democrats won 53.3% of the major party vote--almost two percentage points more--but emerged with just one more seat. The electoral math clearly favors the Republicans now.The best part is, once your unelected presidents and Congress bring in right-wing Supreme Court justices, you no longer have to worry that gerrymandered districts will be declared unconstitutional!
...how much is 53% of the major party vote usually worth? The answer, on average, is 246 seats, thirteen more than the Democrats collected (although to be fair, most of the data points come from the era of the Democratic solid south, which does seem, at first glance anyway, to have given the Democrats more seats with less votes, perhaps because southern turnouts were so low.) And as a matter of fact, when the Republicans took over the Congress in 1994, they won only 230 seats with the same 53% of the major party vote, suggesting that they overcame a considerable Democratic districting advantage. That advantage did not last, however--in 1996, the Republicans kept the control of Congress with 228 seats to 217, even though the Democrats actually outpolled them in the popular vote for Congress. (I do not recall seeing any mention of that rather anomalous result at the time, and this was the first I had heard of it.)