During the next three weeks, the debates are Romney's last chance to change voter opinions. Obama already has a core number of electoral votes, plus many major swing states in his favor, most notably Ohio, Virginia and Florida. Even if things changed between now and election day, and Obama lost Florida, where he currently has a 65% chance of winning, all he needs is one smaller swing state like Wisconsin, Iowa, New Hampshire, Nevada, or Colorado to win. And he already has at least a 65% chance or higher of winning these states. The probabilities are based on economic data and polling data. At this point, something significantly damaging would have to occur for Obama not to win in November, which is possible, but not probable.
Obama excels in national security (especially, after Bin-Laden's death), foreign relations and domestic policy. He's a bit weakness on the economy. The Obama team knows this, and knew this would be a problem from day one. Remember during Obama's inaugural address, he set the stage of the economy and blamed it on W Bush. Now four years later, Obama is basically portraying Romney's policies as W Bush policies II. It seems to be working, unless during the debates Romney can come up with some new are ideas as to how his economic policies differ from Bush it will be difficult for him to win in November.