Romney’s pollster, Neil Newhouse, said his research shows the smaller universe of undecided voters already has reached a conclusion on Obama but has yet to do so on Romney.

“Here’s the advantage we have: You look at the attitudes of those undecided and they are not undecided on Barack Obama,” Newhouse said. “They’ve decided on Barack Obama. They’re not voting for Barack Obama. These are not voters who are open to Barack Obama. The only candidate they’re still trying to figure out is Mitt Romney. There is opportunity for movement on those voters, getting them out to vote and defining who Mitt Romney is.”

Voters have had one term to learn about Obama after his unlikely victory in 2008.

Jeff Jones, Gallup’s managing editor, said the latest polling tracks with typically lower undecided numbers during presidential reelection campaigns. He said a barrage of negative advertising by the campaigns and outside groups also has led voters to make up their minds earlier. This year’s August figures are similar to where the 2008 undecided numbers were by mid-October, he said.