One of McCain's worst moments during the debate was when Obama was calling for more civility during the campaign, but McCain brought up Obama's connection to former 1960s radical William Ayers.
"We need to disagree without being disagreeable," Obama said. But McCain argued, "We need to know the full extent of that relationship [with Ayers]."
Many organizations that conducted instant dial polls during the debate found that when McCain brought up Ayers on his own without being prompted, voters' dials went south very, very quickly.
It was a tactical mistake. McCain is already seen by many voters as going negative during the campaign.
McCain misstated Obama's position on health care when he claimed people like Wurzelbacher and small businesses would be fined under Obama's health care plan. That's not true.
McCain also misstated how Obama's tax plan would affect small businesses.
But Obama was wrong when he said all of McCain's television ads have been negative. That's not true. Obama also underplayed his connection to the community organizing group Acorn.
Ultimately, McCain didn't do enough to stop people from voting for Obama. Over the course of three debate the Obama campaign met their goal of reassuring the American people that he's ready to serve as president.
The only thing that McCain could have done tonight to change the tenor of this campaign was to get under Obama's skin or force him into making an error but that did not happen.
Obama has won every presidential debate he's had with McCain by staying cool under pressure.
Polls suggest Democratic and undecided voters have come away from these debates saying they are more reassured about Obama after the debates.
If the election were held today, Obama would win more than 300 electoral votes. A candidate needs 270 electoral votes to take the White House.
Obama may look back on these three debates and say it was where he sealed the deal.
However there are still two and a half weeks left of the campaign -- and anything can happen in politics.