Low Polls and Gerrymandering Blues

While waking up to read more good stuff on how Bush is tanking in the polls across the board, I cannot help but ask: what does Bush's unpopularity have to do with Dem success in 2006? Redistricting has ensured that Republican and Democrat seats are going to remain Republican and Democrat seats. Every time I get an email from a progressive organization telling me that now is the time for the Dems to take back Congress, my pesky academic skepticism creeps in.

The NYT reports:

Although the composition of Congressional districts will make it hard for the Democrats to recapture control of Congress in the fall, the poll suggested that the trend was moving in their direction. Just 23 percent said they approved of the job Congress was doing, down from 29 percent in January. That is about the same level of support for Congress as in the fall of 1994, when Republicans seized control of the House.

Americans said Democrats would do a better job dealing with Iraq, gasoline prices, immigration, taxes, prescription drug prices and civil liberties.

Fifty percent said Democrats came closer than Republicans to sharing their moral values, compared with 37 percent who said Republicans shared their values. A majority said Republican members of Congress were more likely to be financially corrupt than Democratic members of Congress, suggesting that Democrats may be making headway in their efforts to portray Republicans as having created a "culture of corruption" in Washington.

By better than two to one, Democrats were seen as having more new ideas than Republicans. And half of respondents, the highest number yet, said it was better when different parties controlled the two branches of Congress, reflecting one of the major arguments being laid out by Congressional Democrats in their bid to win back the House or the Senate.

The bolded text being the material point here. What would the polls have to say in order for hardcore Republican districts to all of a sudden vote a Democrat into office? How many seats are really at play (that is not a rhetorical question)? Someone explain to me how the Dems can take back Congress given the effects of gerrymandering?

UPDATE: Scott answers my question over at LGM. Read it and weep.