Republicans were unable to put a replacement candidate on the 22nd District ballot after DeLay resigned from Congress in June because courts had ruled that the party could not put a different candidate on the ballot after DeLay had won the primary. The Houston Chronicle/KHOU poll's margin of error was 4.5 percentage points.
From the October 30 edition of CNN's Situation Room:
KOCH: Wolf, the White House does believe that the president's appearances help, or else they wouldn't be putting him out there. As a matter of fact they're putting him out in these very tight districts, tight races, where they think the president can do the most good. He's in Sugar Land, Texas, or will be shortly, speaking to a crowd of about roughly 7,000 in an airport hangar and campaigning for, among others, the Republican write-in candidate who wants to fill former House Majority Leader Tom DeLay's seat, and it turns out that candidate, Shelley Sekula-Gibbs, is now neck-and-neck, tied actually, with her Democratic challenger.