The first female Speaker’s famous iron grip on her Caucus has been shaken lately by another woman.

Speaker Nancy Pelosi (D-Calif.) has made passing a jobs agenda her top priority this year, but an anti-deficit insurgency led by Rep. Stephanie Herseth Sandlin (D-S.D.), the administrative co-chairwoman of the fiscally conservative Blue Dog Coalition, has forced Pelosi to scale back her ambitions.

With concerns about deficits rising and rank-and-file Democrats fearing losses in November, Blue Dog clout has soared in recent weeks, and liberal priorities from health care benefits for the jobless to tens of billions of dollars in aid to the states have ended up on the chopping block. In the tumult, Herseth Sandlin has emerged to head a new generation of Blue Dogs as old-guard members such as Rep. John Tanner (D-Tenn.) are heading for the exits or lowering their profiles.

The pivotal moment came shortly before the Memorial Day recess, with Pelosi planning to push through a nearly $200 billion package of tax cut extensions, doctor payments, jobless benefits and state aid. But Herseth Sandlin warned the measure didn’t have the votes and would have to be trimmed significantly.

“While we’ve been invited to share our concerns and leadership has listened, not everyone is hearing us,” she told reporters at the time.

Within a day, Democratic leaders were forced to carve their bill nearly in half in a mad scramble for votes.

And this week, the leadership’s plans for a war spending bill had to be cut back in the face of demands from Blue Dogs that add-on aid for states and money for the Pell Grant program be fully offset. The bill will include just $10 billion to prevent teacher layoffs — less than half the amount sought by leadership and President Barack Obama.

“They are starting to hear us,” Herseth Sandlin said.

But the smaller pie is a big disappointment for members of Pelosi’s liberal inner circle, such as Education and Labor Chairman George Miller (D-Calif.).

“Sure, it’s frustrating,” Miller said, pointing to the continuing economic troubles as an emergency.

“There’s concern in the markets about what’s going on at the state level, and it’s counterproductive to do it the way they want to do it,” Miller said of the Blue Dogs.

The backlash is such that other liberals such as Progressive Caucus Co-Chairman Raúl Grijalva (Ariz.) have grumbled recently about paying their Democratic Congressional Campaign Committee dues out of concern it will go to Blue Dog members and other candidates with more conservative agendas.

Rep. Barbara Lee (D-Calif.), chairwoman of the Congressional Black Caucus, ripped the idea that an emergency jobs package must be paid for, noting that the pay-as-you-go law championed by fiscal conservatives has an exception for emergencies.

“People desperately need jobs, and it’s a shame and a disgrace that it’s not declared an emergency,” Lee said.

But Herseth Sandlin said she is gratified to see a renewed interest in the deficit in the House, Senate and country as a whole. She said the issue has gone far beyond Blue Dogs.

“It’s not just a Blue Dog concern any more,” she said. “Blue Dogs … are grateful that we finally have not only some wind at our backs in terms of public sentiment, but we have colleagues in our Caucus and Republicans who are now expressing the same amount of concern about the debt and deficits that we’ve been expressing for a number of years, regardless of who has been in the White House and who has been in control.”

She said the Blue Dogs have had to stick together to force leadership’s hand on several occasions and complained that too many bills have been hashed out in leadership conference rooms, typically dominated by liberals, rather than through regular order.

“We just have to be the squeaky wheel or we’re not going to get through that inner circle,” she said.

A House Democratic leadership aide defended the Speaker’s record of working with Blue Dogs and delivering items they wanted, such as a PAYGO law. The aide also pointed to extensive hearings and markups on energy and health care bills and said the biggest problem with getting jobs bills passed isn’t the legislation itself but the fact that bills are “stuck in the Senate.” The aide also noted that Blue Dogs who hail from districts with high unemployment rates have been supportive of the bills, even if Herseth Sandlin isn’t.

On the tax extenders bill, Herseth Sandlin said the Blue Dogs’ goal wasn’t to delete health funding extensions for the uninsured or other pieces of the bill but to put in place a shorter-term extension so they could be subject to better scrutiny and hearings, as well as offsets. Yet when the items were shorn from the bill, she said, the Blue Dogs got the blame.

“It is a messy way of legislating,” she said. “What leadership is starting to realize is that everyone needs to be included in these discussions earlier.”

The South Dakota Democrat said she feels increasing confidence that she is representing the center of American politics, which she said is too often lost in the battles of the extreme elements on both sides. “The center of America deserves a voice too,” she said.

And she said she believes the White House understands that the present fiscal course “isn’t sustainable.”

“How do you keep the foot on the gas in the short term to help grow the economy … and at the same time build in discipline and reforms to take on the debt?” she said.

Blue Dogs won another victory in this year’s budget battles by extracting a $7 billion cut from Obama’s budget request — a level that will likely force cuts to some domestic spending programs treasured by liberals.

Fellow Blue Dogs say Herseth Sandlin brings the right temperament and a sharp mind to the cold calculus of cutting the deficit, with an ear for politics and the chops to hash out policy details with leadership.

“Stephanie is a star,” Rep. Jim Cooper (D-Tenn.) said. “She’s come into her own. She’s got much greater confidence and a steelier backbone.”

“That’s what a good legislator does — she speaks truth to power and she doesn’t shy away from that,” said Rep. Dennis Cardoza (D-Calif.), who represents Blue Dogs in leadership meetings. “It’s never easy to stand up to the Speaker and the Majority Leader,” he said. “You have to learn to get your sea legs, and she has learned that role.”

Democratic Caucus Chairman John Larson praised Herseth Sandlin as “a breath of fresh air” and said that although they sometimes disagree, she’s still looking for ways to get something done.

“She’s not a ‘just say no’ person. She’s looking for a third way,” the Connecticut lawmaker said. “That’s been her M.O. since she got here.”

Herseth Sandlin has floated alternatives, such as giving states the option of getting an upfront cash infusion for Medicaid or other programs but have the money eventually come out of state aid in the future when the economy presumably will be better.

She faces a potentially tough race back home for a fifth term, and she’s widely seen as potentially running at some point for governor or Senator. Her votes against a slew of Democratic priorities — from the health care bill to this week’s stand-alone bill extending unemployment benefits — have frustrated some Democrats behind the scenes, in part because it undercuts the party’s attack line that Republicans are callously putting deficits above the needs of millions of unemployed Americans.

Herseth Sandlin’s new influence tracks with an internal shift in the Blue Dogs’ leadership structure. Tanner’s retirement leads a mini-exodus of Blue Dog veterans, along with Reps. Marion Berry (Ark.), Bart Gordon (Tenn.) and Dennis Moore (Kan.), leaving the group in need of fresh blood.

Herseth Sandlin said she’s humbled by the support of her Blue Dog colleagues and is ready to step up. She said that her son, 18-month-old Zachary, has made her even more committed to the Blue Dog cause.

“Having a baby puts a whole new perspective on things and grounds you even more, and I feel emboldened in the work that I’m doing to try and force the tough decisions that aren’t always going to always be popular decisions, that at times have strained my relationships with my supporters back home or my colleagues,” she said. “I feel the same anxiety that I think my constituents do, for fear that my child’s generation is going to not be as well off, or to struggle in ways that my generation didn’t, and we just can’t continue business as usual here in Washington.”

Tory Newmyer contributed to this report.