His campaign had hoped that would reinforce his stance as a leader that put the country first. But to many people it instead reinforced the notion that McCain could be impulsive and erratic.
There's also the Sarah Palin factor.
That's prompted some women conservative columnists, who once supported her, to call for her to step down for the good of the party.
Governor Palin's favorability ratings among independents are also going down as her unfavorable ratings are on the rise.
Friday night's debate in Oxford, Miss., which did happen despite McCain's calls to have it postponed, has also helped Obama.
A number of postdebate polls show that most viewers thought the Illinois senator did a "better job."