Sen. Saxby Chambliss of Georgia was considered such a re-election shoo-in for most of 2008 that he mostly ignored attacks by his Democratic challenger until two weeks ago.
Unfortunately for the Republican incumbent, by then his one-time 20-plus-percentage-point lead in the polls over Democratic challenger Jim Martin had shrunk to almost nothing.
"Chambliss is in real trouble - he suddenly has a dead-heat race on this hands, which I don't know he expected," said Matthew Miller, spokesman with the Democratic Senatorial Campaign Committee. "Martin has put together a good campaign quietly under the national radar."
The Democrat was expected to pose little if any threat to Mr. Chambliss' re-election bid. The former Georgia House member didn't even win the Democratic primary, finishing second to a suburban Atlanta county official.
However, after a surprising 20-percentage-point runoff victory in August, Mr. Martin's campaign quickly built momentum. He ran television advertisements for weeks without Mr. Chambliss immediately following suit.
Mr. Martin's surge in the polls coincided with Mr. Chambliss' support earlier this month of the Bush administration's $700 billion Wall Street bailout package.
"That's when things started to fall apart for him," said University of Georgia political science professor Charles Bullock.
The Rothenberg Political Report, which in late September placed Mr. Chambliss in its "currently safe" category, now has handicapped the race as "narrow advantage for incumbent party."
A survey conducted Oct. 9 by the Atlanta-based InsiderAdvantage polling firm had the contest in a dead heat, with each candidate receiving 45 percent.
Mr. Martin - like Democratic challengers nationwide - has tried to tie Mr. Chambliss to the failed economy and an unpopular White House.
The race "is not really about Martin, it's about Chambliss and the Bush administration," said Merle Black, political science professor at Atlanta's Emory University and a longtime observer of Georgia elections.
Democrats, who supported the bailout more vigorously than Republicans, have downplayed that the public backlash over the bailout caused a spike in Mr. Martin's poll numbers.
"It's hard to pull out the bailout from the overall economic crisis," Mr. Miller said. "I think the main thing that voters are concerned about isn't so much the bailout as it is the conditions that led to the bailout."
Mr. Martin's surprising success forced the first-term incumbent to begin broadcasting attack TV ads two weeks ago against the challenger, portraying him as a tax-and-spend liberal.
An aggressive voter-registration campaign in Georgia this year is another factor working in Mr. Martin's favor. The effort is expected to boost the state's black voter turnout, which was about 25 percent in the 2004 elections.
"With an Obama candidacy and Democrats doing a far better job than they've ever done in the get-out-the-vote effort, I wouldn't be surprised if the black vote got up to 30 percent of the total," Mr. Bullock said. "If indeed it does that, then this race is even tighter than the polls suggest, and Martin might be even slightly ahead."
Mr. Chambliss' popularity also took a hit last year when he supported immigration reform that was supported by the Bush administration and many Democrats.
A photograph in which Mr. Chambliss appeared with liberal Massachusetts Democrat Sen. Edward M. Kennedy at a pro-immigration reform press conference drew condemnation from the Georgia senator's constituents. Mr. Chambliss eventually switched his position and voted against the measure.
Mr. Martin also raised more money than Mr. Chambliss during the three-month period ending Sept. 30, according to campaign finance reports. Mr. Martin took in more than $1.3 million - by far his best fundraising period. Mr. Chambliss raised about $1.1 million during the same period.
Nevertheless, Mr. Chambliss still holds a decisive fundraising advantage and is expected to hit the challenger hard in the next two weeks.
"He's got plenty of resources to come back and try to put Martin on the defensive," Mr. Black said. "I think Chambliss would be a slight favorite, but he would only be a slight favorite ...if the Democratic tide comes across in November."