Speaker Nancy Pelosi has been playing hardball to try to salvage what she can from the Democrats’ long-stalled jobs agenda. But the California Democrat is testing the limits of her power as she struggles to corral a growing roster of nervous rank-and-filers.

Pelosi is used to getting her way. Time and again the influential Speaker has proven her mettle, even in the face of difficult odds. Yet as the clock ticks toward the challenging midterm elections, Pelosi is finding no lift is easy — whether it be getting her moderates on board for an extension of tax cuts and expired unemployment benefits or a package aimed at rolling back a controversial Supreme Court decision that lifted restrictions on corporate political spending.

In the case of the extenders measure, a revolt by Democratic moderates and vulnerables just before the Memorial Day recess forced Pelosi to slash the measure’s price tag. But in a press conference afterward, the Speaker brushed off questions about losing intraparty support for the measure; she was adamant that everything in the original package would still become law.

“I believe that everything that we had in the bill will be done,” she insisted last month.

But that’s looking a lot less likely since that scaled-back bill continues to languish in the Senate. And now, Pelosi has started taking hostages.

Last Friday, for instance, after the Senate could only muster a six-month extension of the “doc-fix” to provide Medicare payments to doctors, a clearly frustrated Pelosi threw down the gauntlet.

“I see no reason to pass this inadequate bill until we see jobs legislation coming out of the Senate,” she said in a statement that evening, lamenting the laundry list of initiatives that she has moved through the House that have hit a wall in the Senate.

It was reminiscent of other power moves by Pelosi during her tenure as Speaker, such as when she shoved the Colombia free-trade agreement into a drawer after President George W. Bush tried to force it onto the House floor without her consent, or when she pressured Senate Democrats to agree to pass a reconciliation measure before she would agree to take up the Senate version of health care reform.

This time, however, some think Pelosi may be bluffing, whether she knows it or not. One senior Democratic aide predicted that the House would eventually have to act on the tax and unemployment benefits package, lest they be blamed for failing to keep doctors whole.

She’s also fighting with what many top Democrats have complained is a half-hearted sales job from President Barack Obama for more stimulus measures.

But the bigger problem for Pelosi may be that her iron grip on her own Caucus appears to be slipping.

In addition to having to chop down the extenders package, Pelosi has also shelved the Employment Nondiscrimination Act in a nod to moderates worried about their re-election prospects. And when it comes to the campaign finance measure, the Speaker has had to enlist powerful allies in Obama and Senate Majority Leader Harry Reid (D-Nev.) to try to persuade her Members to come aboard.

One fiscally conservative Blue Dog said that there is a growing tension between a liberal Speaker from San Francisco and her inner circle and moderate Members who sense an electoral “tidal wave” coming their way.

“That’s what you get when you have a Speaker from a D+30 district. Most of us can’t even imagine a D+30 district.”

This lawmaker said Members had been willing to give Pelosi the benefit of the doubt before, but their patience has run out. “I think more people believe [political analyst] Charlie Cook that she might not be Speaker next year. The attitude now is every man and woman for themselves.”

The Democratic lawmaker said that previous leadership promises — that the stimulus would bring down unemployment or that the health care bill would grow in popularity once it became law — also haven’t borne out, making some rank-and-file Democrats wary of sticking their necks out again.

“All we want is a salad, and all she’s offering is cheeseburgers,” said a chief of staff to one vulnerable House Democrat. “But we’ve come to expect it at this point, given the way everything’s gone this Congress. At some point, she’s going to get caught without the votes.”

This aide predicted growing resistance as more Members, clear of their primaries, are starting to survey their general election chances — with troubling results. “The people who have been voting ‘no’ are going to continue voting ‘no.’ But those who have been voting with her and are starting to put polls in the field are getting a wake-up call,” the aide said.

But Pelosi still has plenty of defenders: Liberals are ecstatic that she is sticking up for the unemployed and fighting to prevent layoffs of hundreds of thousands of teachers.

And one senior Democratic House aide said Pelosi was simply sticking up for her chamber’s prerogatives in rejecting the Senate-crafted patch on Medicare payments to physicians. “What the Senate did was political grandstanding of the worst kind,” this aide said.

A House Democratic leadership aide said Pelosi’s intent is to force Republicans to pay a price if they are going to keep blocking measures designed to create jobs.

“If we are not going to be able to get some jobs legislation through because of Senate Republicans, then damn it, people are going to know it all across this country,” the aide said.

And the aide said that Pelosi has been sensitive to moderate Democrats’ concerns all along, backing items such as pay-as-you-go budgeting and agreeing to a bipartisan fiscal commission to deal with the deficit.

Pelosi herself has downplayed any talk of intraparty strife. “Every bill here is a heavy lift,” she said after chopping down the extenders package. “It wasn’t heavier today.”

And she noted she hasn’t always gotten everything she wants. “I didn’t get a public option or anything in the health care bill either.”