National Democrats fighting to hold the Senate have decided to spend another $1 million in support of Michelle Nunn here in Georgia, suggesting that their internal polls say the seat as still within reach. Republican polls appear to be telling the same story, because the GOP decided on Friday that it needed to spend another $1.45 million to get David Perdue over the finish line.

And this morning, we get confirmation. The latest SurveyUSA poll, conducted for 11 Alive, gives Nunn a three-point lead over Perdue and, at 48 percent, within reach of the 50 percent hurdle that would give her an outright win on Nov. 4. Democrats in general fare pretty well in the poll; gubernatorial candidate Jason Carter is in a tie with Nathan Deal, as is school superintendent Valarie Wilson in her contest against her GOP opponent, Richard Woods.

But Nunn is the story. As the pollster describes her momentum:

"Week-on-week, Nunn has gained ground among men, where she now trails by 3. (Five weeks ago, she trailed among men by 19.) Among Independents, Nunn has closed to within 6 of Perdue (she had trailed by 28 points among Independents in August). In greater Atlanta, Nunn had led by as few as 10 points, but today leads by 22."

It's just one poll, but it comes at a time in the political season when campaigns really begin to take form, and when the impact, if any, of Perdue's testimony about his outsourcing career should begin to show up. I'll also admit to being surprised by Nunn's campaign abilities. Derided as a manufactured candidate after the leaking of her internal campaign plans, she now comes across as more sincere and natural than her opponent, while it's Perdue who seems pre-programmed by his handlers and unable to vary from a script that requires four mentions of Obama per sentence.

I've thought from the beginning that Nunn had less of a chance than Carter of pulling off an upset. That may no longer be the case, not because Carter's prospects have dimmed, but because Nunn's have brightened.