Senate Democrats on Wednesday were as upbeat about their midterm election prospects as they have been in several months, celebrating Sen. Blanche Lincoln’s hard-fought primary runoff victory Tuesday night and expressing optimism that Majority Leader Harry Reid may be making a comeback.

Reid continues to poll poorly with Nevada voters, but former state Assemblywoman Sharron Angle’s emergence as his Republican challenger this fall has buoyed his Democratic colleagues, who believe the broader electorate will reject her particular brand of conservatism. Meanwhile, Lincoln’s unexpected 4-point victory over Arkansas Lt. Gov. Bill Halter seems to have stemmed the incumbent bleeding — at least temporarily — providing vulnerable Members some hope heading into November.

Sen. Tom Carper (D-Del.) offered that Republicans probably would have “run the table” had the midterm elections occurred in late January when Sen. Scott Brown (R) won a Massachusetts special election to succeed the late Sen. Edward Kennedy (D). But Carper predicted Wednesday that, come Nov. 2, the economy will have improved, the federal deficit will be smaller, and the new health care law will have grown more popular.

“I think that will help Harry; I think that will help a lot of Democrats running for the House and Senate,” Carper said.

Carper is not up for re-election this year. But even Democrats who are — including those facing potentially tough races — were upbeat about their chances for success this fall. Senators expressed similar enthusiasm when asked to rate Lincoln’s and Reid’s prospects. Lincoln is set to square off against Rep. John Boozman on Nov. 2.

Senate Democratic Conference Secretary Patty Murray (Wash.), who is locked in a competitive re-election battle against likely GOP nominee Dino Rossi, said her caucus is “pretty upbeat” after Tuesday’s primaries and “ready to keep going to the fall.”

Sen. Barbara Boxer, who won decidedly in Tuesday’s Democratic primary in California and will now face former Hewlett-Packard CEO Carly Fiorina (R) in the general election, also sounded confident.

“In our race, it’s pretty clear. I’ve got someone who’s running on her record at Hewlett-Packard. … She got fired. She got a $20 million severance pay, and she’s using it to buy a seat,” Boxer said. “Her attack on me is that I’m an incumbent. Well, I chose to have a life of public service and I’m proud of it.”

Boxer noted that she garnered more primary votes than Fiorina and the second-place GOP finisher, former Rep. Tom Campbell (Calif.), combined.

Senate Republicans were content to let the Democrats enjoy the results of Tuesday, which featured the largest number of primary contests on the ballot this election cycle.

The political atmosphere has been challenging for the Democrats this cycle, and Republicans believe that the environment hasn’t changed.

If anything, Republicans appeared amused by the Democrats’ fresh optimism: Senate GOP Conference Chairman Lamar Alexander (Tenn.) brushed aside suggestions that Democrats are less vulnerable today than they were when the week began.

“They must have had a very bad previous week to think yesterday was a good day,” Alexander said with a chuckle.

“Their nominee in Arkansas is 25 points behind the Republican nominee according to the latest average of polls on Real Clear [Politics], and their party is deeply divided,” Alexander added. “In Nevada, a complete newcomer begins the race already ahead of the Majority Leader of the United States Senate. So, we have a long way to go until November, but all the signs point to a very good year for Republicans.”

To be sure, Angle was the candidate Reid wanted to face out of the three frontrunners in Nevada’s GOP primary field. Still, the news was not all good for the Majority Leader. Tuesday’s elections saw GOP primary voters outnumber Democratic primary voters 175,671 to 116,005. And 10.6 percent of Democratic primary voters selected the “none of these candidates” choice offered on the ballot, rather than voting for Reid.

But even some experienced Republican consultants familiar with Nevada politics lack confidence in Angle’s ability to oust Reid. The Republican, backed by tea party activists and the conservative Club for Growth, is controversial: She supports privatizing Social Security and Medicare and wants to do away with several government agencies.

Said one GOP strategist, flatly: “She can’t beat Reid.”

It was clear Wednesday that the Democrats wholeheartedly agree. Additionally, they were heartened by Lincoln’s victory in a race in which she was targeted for defeat by liberal Democratic interest groups and organized labor, which spent $10 million in the contest

“We feel good about the result that Blanche had last night. You know, Blanche is somebody that all of us like a lot. She’s a good legislator, and we’re pleased that she got through this,” said Sen. Byron Dorgan (D-N.D.), who opted against running for another term this November. “And Sen. Reid has a tough job; the things that he has to do as Leader sometimes make it a more difficult job. But I think his numbers are improving, and I think all of us feel better about his situation in Nevada.”

Sen. Chris Dodd said there is a big difference between the perception of the anti-incumbent zeal and the reality on the ground in many states. Facing his own abysmal poll ratings back home, the Connecticut Democrat in January also decided to retire rather than seek another term.

“I never thought it was going to be as bad as people thought two months ago,” he said. “As long as between now and then we keep focusing on jobs and getting the economy moving and don’t get off on a sidetrack of unrelated issues from what most people care about, I think we’ll be fine.”

Senate Democratic Conference Vice Chairman Charles Schumer (N.Y.), who led the Democratic Senatorial Campaign Committee in the 2006 and 2008 cycles, agreed that Democrats are feeling more bullish but offered a few words of caution.

“Today’s a day that we’re feeling pretty good,” he said, “but we can’t be complacent.”