With third-party Libertarian candidate Allen Buckley pulling votes away from both Chambliss and Martin, it's possible that neither the Democrat nor the Republican will achieve the 50 percent of the vote that is required for victory under Georgia law, stretching the race into a Dec. 2 run-off on and possibly leaving Democrats teetering around the 60 Senate seat mark for nearly a month.
While Obama is not expected to capture Georgia's 15 electoral votes, a recent CNN/Time/ORC poll has him trailing McCain by just five percentage points, 52-47. An overwhelming number of African American voters have turned out to vote early in the state, a result of the Democratic nominees' surging popularity.
"This is a Southern area where Obama's success and excitement could at least close the gap," said Zelizer.
The economy has been another huge issue in Georgia, where Chambliss has been criticized for his support of the $700 billion financial bailout plan that Congress approved last month.
Minnesota is another state where a third-party candidate is complicating the issue. Independent Party candidate Dean Barkley isn't making things easy for Republican incumbent Sen. Norm Coleman and comedian-turned-Democratic challenger Al Franken (yes, that Al Franken).
But Minnesota does not have a 50 percent rule similar to Georgia's, so either Coleman or Franken could win the seat with less that 40 percent of the vote.
Barkley, according to political experts, has been successful in garnering support from voters who are tired of the Coleman and Franken horserace.
"Barkley is sort of the opt out choice for people who are sick of Coleman and Franken," said Duffy. "Watch Barkley's number all night -- I'd expect whoever wins might only win with 38 or 39 percent of the vote."
Duffy adds that while Obama has been doing well in Minnesota -- the Star Tribune/PSRA poll shows him leading McCain 53-42 -- voters in the state have been known to split their tickets.
"I wouldn't be surprised to see Coleman do well even if Obama is doing well," said Duffy.
Zelizer said that while Coleman has remained popular during his tenure in the Senate, he has suffered from "the implosion of the GOP."
The latest poll by the Star Tribune/PSRA on Oct. 31 has Franken leading Coleman 42-38
"Like Dole in North Carolina, Coleman is being dragged down by a party he is often at odds with," Zelizer said.
Sen. John Sununu's father once helped run the White House, and the Sununu family is as prominent as you get in state Republican quarters. But Sununu has been behind for most of his race against Democratic challenger Jeanne Shaheen, who lost to Sununu six years ago by just four percentage points.
In this year's race, the most recent AP/GfK poll has Shaheen leading Sununu 47-41.
David King, a public policy lecturer at the Harvard Kennedy School of Public Policy in Massachusetts, said that both Sununu and Shaheen have been using the same tactic of tying the other to President Bush.
Sununu repeatedly points out that Shaheen has supported many of Bush's policies. But an association with Bush to some degree, said King, may actually help the Democrats.
"To moderate conservatives it has even made Shaheen seem more acceptable," said King.
King added that Sununu's popularity in the state and his strong campaigning might push him over the top again.