Senate Democrats just can’t seem to catch a break.

The revelation Monday that Sen. Chris Dodd’s (D-Conn.) would-be successor — Connecticut Attorney General Richard Blumenthal (D) — made misleading statements about his military service added one more headache to Democrats still reeling from unexpected retirements, unplanned and contentious primaries, and other disappointments on the 2010 campaign trail.

As they’ve struggled to build public support for their agenda and fought an emboldened Republican opposition, Senate Democrats are also gradually realizing that they may be looking at a loss of at least half a dozen seats in November.

Blumenthal’s subsequent mea culpa Tuesday for leading people to believe that he served in Vietnam, when in fact he served in the stateside Marine Reserves in the 1970s, could put another otherwise safe Democratic seat into play and give Republicans a better chance of retaking control of the chamber this fall.

Blumenthal was supposed to be the knight on the white horse who saved Democrats from certain defeat in Connecticut had Dodd remained on the ballot. Dodd announced his decision to retire, reluctantly, in January, and Blumenthal has been the favorite to win ever since.

But the news about his military service — broken by the New York Times late Monday — could be a game changer. Blumenthal quickly tried to contain the damage on his own, saying at a Tuesday afternoon news conference, “On a few occasions I have misspoken about my service, and I regret that and I take full responsibility.”

And some Congressional Democrats also rallied to his side.

“I think, you know, his actions as it relates to standing up for veterans over a long period of time speaks volumes [about] both where his heart and his actions are,” Democratic Senatorial Campaign Committee Chairman Bob Menendez (N.J.) said. “I’m sure he will continue to stay in the Senate race, and we will continue to support him.”

Dodd defended Blumenthal as an “honorable” man: “I know Dick Blumenthal. My support for him is unwavering, and I think he’ll be a great United States Senator.”

But others declined to comment or said they would reserve judgment.

“He essentially said he made a mistake, and he regrets it, and, you know, the campaign goes on,” said Connecticut Sen. Joe Lieberman (ID), who weathered a tough re-election fight of his own in 2006. “I remain where I’ve been, a good Independent waiting to see who both parties nominate, and then I’ll decide whether to get involved. He’s been a good attorney general.”

The Blumenthal dust-up is the latest curveball Democrats have been thrown in what was already a tough cycle.

In January, Dodd’s retirement was preceded by a less welcome departure, when Sen. Byron Dorgan (D-N.D.) surprised the party by announcing he wouldn’t run again. The seat is now expected to be won by a Republican.

Then, Sen. Evan Bayh (D-Ind.) threw another relatively safe Democratic seat into play when he too decided not to seek re-election.

Add to that the subsequent special election loss of the seat held by the Senate’s liberal icon, Sen. Edward Kennedy (D-Mass.), to the tea-party-fueled candidacy of Sen. Scott Brown (R).

As of press time, Democratic convert Sen. Arlen Specter (Pa.) was fighting for his political life against Democratic Rep. Joe Sestak, and Sen. Blanche Lincoln (D-Ark.) was in danger of facing a primary runoff against Lt. Gov. Bill Halter.

And the road ahead doesn’t look much brighter: Republicans are in a position to pick up a symbolic trifecta this year, if they win against Senate Majority Leader Harry Reid (D-Nev.) and best the Democratic candidates to retake the seats once held by President Barack Obama in Illinois and Vice President Joseph Biden in Delaware.

Yet even with Blumenthal adding to Democrats’ electoral woes, Senators said Tuesday that they are not yet giving up on their ability to win this year.

“I don’t think anybody’s dispirited,” Sen. Claire McCaskill said. “We’ll see. I think a lot of things we’re doing are the things we got sent here to do: solve hard problems. And you can’t solve hard problems and keep everybody happy.”

The Missouri Democrat added that predictions of dire Democratic losses have only energized her and other Democrats to work harder. “You know, November is still a long way away. I like where the expectations are right now. … I’ve always cherished the role of an underdog.”

Sen. Bob Casey agreed, saying Democrats are in a better position now than they were in January. The Pennsylvania Democrat has been campaigning hard for Specter’s bid.

“I don’t think we should get too worried about the day-to-day difficulties that we have,” Casey said. “Some of them we can control and have an impact on, some of them are out of our control. The one thing we can control is maintaining our focus on jobs and the economy.”

He added, “I think it just so happens that there’s a confluence between focusing on job creation and the economy as being both substantively the right thing the do and politically helpful.”

Senate Democrats are cautiously optimistic, though, that Blumenthal will be able to salvage his candidacy, even as they admit the accusations have damaged him.

They point to the fact that veterans stood with Blumenthal on Tuesday to defend him against the Times article, and at one point, they even tried to shout down a reporter who asked a question they felt was unfair.

But Blumenthal’s GOP opponents, who will face off at a state party convention this weekend, pounced on the revelations. “I think his press conference was very inappropriate,” said former Rep. Rob Simmons, who served in Vietnam. “Why would he have a press conference in a [Veterans of Foreign Wars] hall? He’s not eligible to be a veteran of foreign wars because he never served in Vietnam. … The press conference was in the nature of a pep rally.”

Of course, Republicans have had to deal with a few of their own hiccups. The most obvious is Florida Gov. Charlie Crist, the once-establishment Senate candidate who bolted the GOP to run as an Independent when the political tides turned against him. His new party label gives Democrats fresh optimism about the seat, which is being temporarily held by former Crist aide Sen. George LeMieux (R).

Other Republican frontrunners have suffered from gaffes as well, including former Nevada state GOP Chairwoman Sue Lowden — the current leading contender to take on Reid in November.

And in Kentucky, Trey Grayson, the establishment choice in the race to replace Sen. Jim Bunning (R), appeared set to lose Tuesday to ophthalmologist Rand Paul, son of Rep. Ron Paul (R-Texas) and a tea party upstart who Democrats feel will be too far to the right to win this fall.

“Nobody ever thought this cycle was going to be a walk in the park, but that is why you’ve seen Democrats do everything possible to prepare, including recruit strong candidates, outpace Republican fundraising and aggressively define our opponents,” DSCC spokesman Eric Schultz said Tuesday.