Democrats' hopes of retaining their Senate majority soared recently when Republican Sen. Olympia Snowe announced she would not seek re-election in Maine.
Just a few weeks later, however, Democrats are now far less certain they'll be able to capture Snowe's blue-state seat, or hold their four-seat Senate majority, now that a popular independent candidate has jumped into the race.
"Now it is kind of a jump ball," Jennifer Duffy, a senior editor at the Cook Political Report, which analyzes the races, told The Washington Examiner.
The turn in fortunes is typical of challenges facing Democrats, who must defend 23 seats in the November elections while Republicans must protect just 10. Moreover, seven Democratic incumbents are in "toss up" races, compared to just three Republican incumbents facing too-close-to-call races, Duffy said.
Given the daunting odds, Democrats were eager to add Maine to their victory column and Snowe's retirement was welcome news.
But when the state's filing deadline arrived last week, a less-than-stellar lineup of Democratic candidates had thrown their hats into the ring.
Maine's Democratic establishment wanted one of two members of the House, Mike Michaud or Chellie Pingree, or former two-term Gov. John Baldacci, to run. But all three opted out, and the leading candidate who remains is independent Angus King, whose mixed political history includes his support of both George W. Bush and President Obama.
"There's no question the Democrats would have preferred to have one of their own in this seat," Bates College political science professor John Baughman told The Washington Examiner.
King's political allegiance remains murky. While Baughman and others believe he is likely to join with Senate Democrats if elected, King has refused say to which party he would vote with once elected.
In addition to Maine, Democrats are also feeling let down in Massachusetts, where their star candidate, Elizabeth Warren, is slipping in the polls in her bid to unseat freshman Republican Sen. Scott Brown. Brown's race is one of the GOP's three "toss up" races, though it could slip from that category.
Warren soared in the polls ahead of Brown, the first GOP senator from Massachusetts in decades, when she announced her candidacy in September. But her numbers have dropped significantly and she now trails Brown. Some political observers believe Brown will maintain his lead heading into the November election, but others say it is too soon to tell which candidate will prevail in a state where Democrats vastly outnumber Republicans, but independent voters make up 52 percent of the vote.
"I think it is going to be a very back-and-forth race like this, unless there is some cataclysmic development in either campaign," said Boston-based Democratic strategist Mary Anne Marsh."This is going to be a five-point race either way."
Republican strategist Ron Bonjean told The Examiner that control of the Senate hinges not just on individual races but on the nation's economic environment.
"It is going to be very close," Bonjean said. "But it is a bad environment to be a Senate Democrat with high gas prices, high unemployment and low enthusiasm of voters to keep incumbents."