What poll suggests that Bush won the 2nd debate?
In any case, the 3rd debate definitely matters...Bush is up by 2%, and Kerry gained 3% on him in the first debate, so a similarly strong performance could easily put Kerry over the top.
The impression I got (from coverage - I didn't stay up into the small hours of morning to watch it live on German TV) was that Bush did better than the first time, kinda about/almost (take your pick) as good as Kerry. But that that impression may be coloured by lowered expectations (ie, Bush still s*cking but not as royally, people comparing him to himself rather than to Kerry).