Majority Leader Harry Reid (D-Nev.) has been walking around the Senate lately with a broad smile, his shoulders back and a hint of a swagger.

It’s a far cry from the hunched, almost sullen Majority Leader of earlier this year when his party lost a crucial filibuster-breaking seat in the chamber, the health care debate seemed unwinnable, he was trailing badly in re-election polls back home, and his own rank and file were agitating for their leaders to be more aggressive against GOP obstructionism.

“I think everybody is feeling very good about Harry,” Sen. Sheldon Whitehouse (D-R.I.) said.

There’s no doubt it’s been a good week for Reid. On Wednesday, Republicans abandoned their three-day filibuster of a motion to begin debate on a Wall Street overhaul, a surrender that played right into Reid’s strategy. Reid kicked off the week with plans to force vote after vote after vote on his GOP colleagues, hoping that if he made them vote “no” often enough, they would finally end the blockade. The tack is a different one for Reid, who spent much of the past 17 months trying to forge bipartisan deals and cobble together a fragile margin of 60 votes on legislation — a goal that often extracted more political pain than gain.

Asked why he appears so upbeat these days, Reid said Wednesday, “I don’t think there’s any one thing. I just think the caucus is very supportive, and I think we’re on the right track on what we need for our country.”

Of course, Reid still has challenges ahead, and one good week does not remake the man. And he faces a serious uphill battle to secure a fifth term this fall. However, he has had a “couple of good weeks in Nevada” one aide said. Indeed, Reid’s most prominent challenger, former state GOP chairwoman Sue Lowden, gave Reid plenty of campaign fodder when she suggested that people might be able to barter for their health care, saying, “Before we all started having health care, in the olden days our grandparents, they would bring a chicken to the doctor, they would say, ‘I’ll paint your house.'”

[IMGCAP(1)]He still trails Lowden in recent polls, but Reid and his caucus feel like he has begun to help them turn the tide in what appeared to be a long, deep slide to legislative and electoral defeat this year — not only for Reid personally but for many of his colleagues.

Senators and aides attribute the change to Reid’s newly aggressive style on the Senate floor and decision to change course when the strategy that was used to pass health care in November, for example, proved to be a loser with the American people.

Reid and rank-and-file Senate Democrats began to second-guess themselves during the health care debate last year, but the reconfigured strategy did not really begin to take shape until after Democrats lost the January Massachusetts special election to now-Sen. Scott Brown (R) — an outcome that gave Republicans a filibuster-sustaining 41 votes.

Though Reid’s position as leader has never been in any serious jeopardy, he appears to have quelled any questions about his leadership abilities for the time being. Many Senators were frustrated with his willingness last year to let bipartisan health care negotiations drag on for months, only to have the GOP mount a united front in opposition when the bill finally made it to the floor in November. As a result, many Democrats felt Reid had allowed Republicans to run circles around them without an adequate counter.

Since Brown’s win, however, Reid has made a series of tactical decisions that have resulted in much-needed legislative wins for his party, including the hardball line of attack he took this week to getting the financial reform bill to the floor, a surgical approach to a job creation measure, and a tough stance on GOP roadblocks — particularly Sen. Jim Bunning’s (R-Ky.) one-man filibuster to extending unemployment insurance.

“People are confident in the path and the tactics that we’re taking,” one senior Senate Democratic aide said. “Momentum builds more momentum.”

Senate Democrats said they are feeling more hopeful than they have in a long time, particularly after they were able to force Republicans to abandon their filibuster of financial reform.

“I think the frustration of the younger Members of the Senate was that we were being filibustered and nobody knew it,” Sen. Benjamin Cardin (D-Md.) said. “I think that the contribution that the younger Members of the Senate by term made was, ‘Let’s let the public know what’s going on here. Let’s keep an issue on the floor and debate it even if we can’t win it.’ We did that, as you know, on the unemployment extensions and it worked. And I think the same is true on the Wall Street reform … The younger members of the caucus were more vocal about it, but I think our leaders were very sensitive to it.”

Cardin added that Reid was not necessarily to blame for failings of the past year, given that Democrats were eager last year to find bipartisan support but became disillusioned when it didn’t materialize.

“I think most of us at the beginning of the session thought that working across party lines was the best way to get things done. I still believe that, but it’s not working. It didn’t work on health care. It didn’t work on the stimulus package. And we’re looking for broader coalitions, and we’re not getting it.”

Meanwhile, Reid has won plaudits from many junior Democrats for encouraging them to highlight the more obscure parts of Republican “obstruction,” such as secret holds on nominees.

Last week, several Senators took to the floor to try to smoke out Republicans who were objecting to President Barack Obama’s executive branch picks ranging from ambassadors to U.S. marshals.

“I think we’ve seen some movement on that,” Sen. Michael Bennet (D-Colo.) said. “I think it is important. People at home want to know what all the fighting is about over these secret holds.”

Whitehouse said Reid and other leaders have given their Members optimism and shown the rank and file a “fighting spirit,” because they changed the way the Conference operates, empowered Members to be more involved and stepped up their public relations game.

Said Whitehouse, “He was willing to go outside the box.”