Three looming debates represent the last, best chance for President Obama or Mitt Romney to force a decisive moment in the presidential race.

The Romney team will be especially eager to maximize the opportunity, in light of several polls showing that Obama has widened his previously small lead since last week’s Democratic National Convention.

The president’s boost from that event might well dissipate in the weeks ahead, but, for now, it has bolstered the confidence of the Obama camp — and deepened worries among Republicans.