When half a million more folks vote for a Democrat Presidential candidate, you’d expect that candidate to be elected. 
I think the biggest factor in the last elections was inertia. Most(perhaps all, I don’t remember) of the sitting Democrats were incumbents. In fact, not a single congressional incumbent, of either party, lost a race in 2002. If the current map is unfair, I don’t think it had much, if any, influence on the elections.
I’m not quite sure how to better explain my objection to the 57% statewide total votes number. I’ve mentioned that this vote doesn’t take into account voter turnout in the various districts. A single candidate who ran a very vigorous campaign and got lots of voters to turn out in his district could cause such an imbalance. That doesn’t mean the other candidates didn’t deserve their wins. My district, district 30(comprised of South Dallas and the lower mid-cities between Dallas and Ft. Worth) has an incumbent by the name of Eddie Bernice Johnson. She is one of the most popular congressmen in the state. She won the last election by one of the largest margins in the entire race, over 50%. Her race was never really in doubt. The candidate who was fielded agianst her had absolutely no prayer. I know several people who didn’t bother to turn out at the polls because the match was a foregone conclusion. Similarly, in the races where the candidates were completely unopposed(three races in 2002, all Democrats), obviously there was no turnout for those candidates to figure into the total number of votes cast for congressmen. No votes were cast for them because they were unopposed. If they had been opposed then their numbers(presumably large margins of victory for the Democrats) would most likely offset the turnout for Republicans because there was no need for it. So the 57% number is inaccurate, at the very least because it is missing three races worth of (probably largely democratic) votes.
Total votes cast in the 2002 elections in Texas was 4,552,059 Source
Each congressman in Texas represents ~660,000 people. Voter turnout from that election year was ~33%. Lets assume those unopposed Democratic incumbents, had they been opposed, would have won by the same kind of landslides we saw in most of the other races. Say 35% margin of victory. So that means 32.5% R and 67.5% D in those races. 660,000/3(to get 33% turnout) is 220,000. 220.000 * 67.5% = 148500 D votes per race and 220,000 * 32.5% = 71,500 R votes per uncontested race. Now we take the total number of votes cast for Congressmen, of which 57% were for Republicans, and 43% for Democrats and add in our made up numbers for the races that didn’t happen.
4,552,059 * 57% = 2594674 R votes for Congressmen. Plus the 3 * 71,500 they would, theoretically, have won if the uncontested races had been run. New total, statewide, of 2,809,174
4552059 * 43% = 2,139,468 D votes for congressmen statewide. Now we add in the 3 * 148,500 they would have won in the uncontested races. New total, statewide, of 2,584,968
New totals for both parties = 5394142
2809174/5394142 = the Republican’s margin of statewide overage if those races had been run. 52% A 5% diffirential from their actual representation.
Now what if we aren’t so generous and we say the votes in those uncontested elections should belong wholly to the Democrats? Well, then we get 220,000 * 3 to add to the D’s total, and nothing to add to the R’s total. Let’s see where their percentages are now.
R congressional votes cast in the 2002 elections = 2,594,674
D congressional votes cast in the 2002 elections = 2,139,468 Plus the votes that were cast for them by default because no one even ran against them. 660,000 = New D congressional votes statewide of 2,799,468 Brings the new theoretical total to the same as before,
5,394,142. So now where do the D’s stand? 2,799,468 / 5,394,142 = ~ 52% Hmm, that’s odd. Now, the D’s seem to be leading. They won ~52% of the statewide vote, even if some of it was by default, and they got ~57% of the representation. Seems fairly close to me.
Have I made my point about how that one statistic is not a silver bullet? Or should I start picking apart the other races where there was not representatives from both parties? Start analyzying voter turnout for the various districts, especially those without strong competition for the incumbent? You know there were four GOP candidates who ran without Dem opposition and absolutely slaughtered their independent, green, and libertarian opponents. Should votes from those races be considered? After all, in the big picture we’re only talking D&R
Nope, I still reject this kind of high-level analysis of the voting results. Do you understand why?
Enjoy,
Steven