While we don’t know the impact of the last debate, the polling indicates that McCain has been able to close the gap with Obama markedly in the past week. Realclearpolitics.com lists six polls with a field date ending on 10-13. Their average gave Obama a margin of 8.3%. There are seven subsequent surveys with a field date ending on 10-16 and their average is an Obama lead of 5.1. The seven polls whose field date ended on the 16th only include one night of post debate polling (usually of a three night sample). As the next few days of polling comes in, the situation should clarify itself.
But we can say that Obama has lost more than a third of his lead in the last week.
If the financial markets stop hogging the headlines and McCain exploits the tax and spending issue he developed (with the considerable aid of Joe the Plumber) it is very possible that he could close the race further, perhaps bringing it to a tie in the next ten days.
This race is far, far from over!