For a brief time in mid-October, some Democrats believed Michelle Nunn, the party's Senate candidate in Georgia, could be the firewall that prevents a Republican takeover of the Senate. If Nunn could win the seat opened by retiring GOP Sen. Saxby Chambliss, then Republicans would need to pick up seven, not six, seats to take control.

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In half-a-dozen polls taken over a two-week period in the middle of October, Nunn led Republican opponent David Perdue in five, while the candidates tied in one. Democratic optimism surged. "National Democrats have just decided to pour $1 million into this race in Georgia, a sign of how important a victory here would be to their effort to beat the odds and hold on to control of the Senate," the Wall Street Journal reported Oct. 17. More pro-Nunn money came after that, with a barrage of ads focusing mostly on accusations the businessman Perdue outsourced thousands of Georgia jobs.

Now, things have changed. Perdue has recovered from the attacks — he indisputably helped create thousands of jobs in his career — and in the last six polls, taken since Oct. 16, Perdue has led in five, while one was a tie. In the RealClearPolitics average of polls, Perdue is up by 2.2 percentage points. In the newest poll, a NBC News-Marist survey released Sunday, Perdue leads by four points, 48 percent to 44 percent.

Perdue's position puts him in striking distance of the 50 percent total required for him to win outright, avoid a January runoff and dash a lot of Democratic hopes.

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Perdue's position will likely be strengthened by his performance against Nunn in their final debate Sunday morning. Or perhaps more accurately, Nunn probably won't reap any benefit from her lackluster performance.

The short version of the debate was that Perdue stayed almost exclusively focused on the issue of jobs, and also tying Nunn to President Obama, while Nunn veered back and forth from trying to associate herself with former President George H.W. Bush to attacking Perdue for outsourcing to distancing herself from Obama. Nunn's was a much more difficult job than Perdue's. She didn't succeed.

The difference was striking from the first question, which asked the candidates to discuss how their prior life experiences qualify them for the Senate. Perdue of course pointed to his business record, but immediately pivoted to his job-creation agenda: tax reform, reduced regulation, a broader energy policy. Nunn, with a background in the nonprofit world, noted that she had worked for the Bush Points of Light organization. Her agenda, she said, was "putting our country first, above party and above partisan divides and actually getting things done," although it is unclear what that agenda actually entails. She also took a shot at Perdue, "who, by his own account, has spent the majority of his career outsourcing jobs."

So: Perdue's first appeal was jobs, jobs, jobs. Nunn's was nonprofits, volunteers, Bush and attacking Perdue. Score one for the far more focused Republican.

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Nunn tried over and over to connect herself to the Bush 1, until Perdue finally pointed out that the president has actually endorsed him and not Nunn. Nunn's Bush talk, as well as the outsourcing charges, Perdue said, were "an attempt at distraction away from the real critical issue in this race, and that is job creation here in Georgia."

As the debate continued, Perdue tied Nunn repeatedly to the Obama agenda. Nunn, in turn, appeared unfazed by Perdue's Bush put-down, continuing to link herself with the first Bush. "I've spent about 45 minutes of my life with President Obama," Nunn said. "I've spent seven years working for President George H.W. Bush's Points of Light organization."

Nunn tried to accuse Perdue of opposing the minimum wage — not just an increase in the minimum wage, but the minimum wage itself. "Well, it's the law of the land," Perdue answered, explaining that he opposes raising the current wage of $7.25 an hour to $10.10. (He did not say whether he would approve of a smaller increase.)

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But Nunn had a bigger problem, as she has had throughout the campaign, with Obamacare. Would she have voted for it had she been in the Senate in 2009 and 2010? "I have said many times that I wasn't there," Nunn answered. "And I do wish there had been more bipartisanship. … I have said many times that I believe we should and must change the things that are not working." Obamacare has "many faults," Nunn continued, listing some of the fixes she would support, like "adding a more affordable tier of insurance."

In the big picture, though, Perdue was all jobs, and Nunn was all over the place.

A longer view of the polls suggests that Perdue has been the natural leader of the race for a long time, except for the brief stretch in October that got Democrats so excited. Now, on the eve of the election, Perdue is ahead again and is within reach of winning outright. For Democrats, winning Georgia was thrilling to consider, for a minute or two, but doesn't appear to be a reality.