For all their outspokenness about the need to fix New Jersey's troubled health-benefits and pension systems, Senate President Stephen Sweeney and Gov. Christie cannot accomplish the job without acknowledging that ultimately the battleground is the Assembly.

"Sweeney can work on whatever deal he would like to work on with the governor," Assembly Speaker Sheila Oliver said. "If it doesn't cut any mustard in the Assembly, it goes no place."

The negotiations are a trying test of the Essex County Democrat's leadership as some insiders are questioning her effectiveness and the majority of her caucus is resisting the proposed legislation.

The stakes are high: Skyrocketing benefits costs have driven up property taxes, and scaling back those benefits and having workers pay more would save millions.

As one of the most powerful women in New Jersey politics, Oliver has pursued a very different philosophy and leadership style from Sweeney since a North-South political deal in 2009 elevated them to the top of the Democratic-controlled Legislature.

"They make a good team because the speaker is able to slow things down when Sweeney is going too fast, and sometimes it works the other way around," said Sen. Raymond Lesniak (D., Union).

Nowhere has that been more apparent than on health benefits and pensions, which Christie, a Republican, has made the cornerstone of his agenda. He wants all public workers to contribute 8.5 percent of their salaries to the pension fund and pay 30 percent of their health-care premiums.

A plan announced by Sweeney in February wouldn't go quite that far - for example, he supports having workers pay between 12 percent and 30 percent of their health benefits, based on how much they make. Details of the plan are being debated privately, and the final version could differ.

But the Gloucester County Democrat, who is working to roll both measures into one mega-bill, has signaled a willingness to buck not only the public-employee unions furious about leaders legislating matters typically negotiated at the bargaining table, but also the majority of his own party. He intends to pass the legislation by rounding up a minority of Democratic senators to supplement votes of Senate Republicans.

"I am not prepared to do that," said Oliver, 58. "As a legislative leader, it's incumbent on me to work with the people who appointed me as the leader of the caucus."

In many other ways, too, Oliver and Sweeney could not be more opposite.

The East Orange resident represents urban North Jersey and works as assistant administrator under Essex County Executive Joseph N. DiVincenzo Jr., the Democratic power broker who helped orchestrate her rise.

Sweeney, who won his spot with the backing of Camden County power broker George Norcross, hails from West Deptford and represents a mostly rural district.

She has an Ivy League master's degree, and he is a union ironworker without a college education.

Oliver hews to traditionally Democratic ideas; Sweeney is more conservative.

Sweeney also had something of a statewide profile before he became president, having served as majority leader and picking fights with the public-employee unions. He openly campaigned to replace Sen. Richard J. "Dick" Codey of Essex County as leader of the Senate.

An assemblywoman since 2004, Oliver came almost out of nowhere to replace retiring Speaker Joseph J. Roberts Jr., becoming the first African American woman to hold the post.

Brigid Harrison, a political science professor at Montclair State University, said Oliver had been at a disadvantage from the outset as speaker. For one, Roberts, a veteran legislator from Camden County, left big shoes to fill in generating loyalty and controlling the caucus.

"She's also stuck with . . . having a very outspoken and successful governor," Harrison said. "And trying to cut her teeth as leader up against Gov. Christie was, I think, an enormous challenge."

Harrison added that while Oliver and other Democrats had tried to provide one voice of opposition, the Senate president had in some ways undercut them.

"Because Sweeney had crossed over on so many issues, it's really hard for them to do that, and I think in many ways that has undermined her ability to lead her caucus," Harrison said.

At times, Oliver can seem like the odd one out, though she, Sweeney, and Christie's office say all are working together.

Oliver partly attributed the closer relationship between Christie and Sweeney to gender.

"I think the Statehouse has historically been a male-dominated environment, without question, and I think it is probably easier for the Senate president, being a male [and having] an image of the iron-pumping ironworker," she said.

Oliver said women communicate and develop relationships differently than men do.

"You've got to hold your ground and do your thing," she said. "You can't be intimidated by that. I'm certainly not intimidated by it."

Sweeney said he had been mistaken in excluding Oliver in the past, pointing to a historic property-tax deal last Fourth of July weekend, in which Sweeney and Christie held a news conference without Oliver.

Sweeney said last week that he should have spoken with Oliver more on that issue but that they had since come together on other issues, such as passing a law to limit raises awarded under binding arbitration for police and fire employees.

On health benefits and pensions, Oliver has proceeded more quietly than Sweeney and is less forthcoming about her plans.

One legislative source said about 15 of the Assembly's 47 Democrats - mainly from South Jersey and Essex County - had lined up behind a combined pension and health benefits bill. Most Assembly Democrats would support a pension bill, the source said, but many in the caucus believe health benefits should not be legislated.

Even if two-thirds of the majority is not on board, the bill could garner enough votes if every Republican in the 80-member chamber joined with the supporting Democrats.

Roberts related with Oliver's position. He said legislative leaders must "make sure that the policies they're advancing have to be in sync with at least a significant number of their caucus, so I understand the challenge. If the leader is out there by themselves, that raises issues about how long they'll be the leader."

Others disagree.

Assembly Budget Officer Declan O'Scanlon (R., Monmouth) said that if Oliver was "deferring to the whims of her caucus and insisting on 50 percent plus one before she'll do anything, that's an abdication of leadership."

Sweeney said the legislation was "really difficult."

"You're not going to get the majority of your caucus on this one," he said. "She's working as hard as she can to get as many of her members on board as possible."

Oliver said the implications of a deal on pension and health benefits - which all sides are working to complete by the end of June - would be profound for cities.

"The only place they're going to find some leverage is to reduce down their cost for health care," she said.

The typical public worker is not drawing a six-figure salary, she said.

"These are not high-level earners, so that is why we have to do this very carefully and not do it in a knee-jerk way," she said.

"Democrats do believe in and support the collective-bargaining process," Oliver said. "That is really what is making this such a difficult issue to come to some consensus on."

Contact staff writer Maya Rao
at 609-989-8990 or mrao@phillynews.com.