SECAUCUS, N.J. - When Gov. Christie in March demanded tighter restrictions in a bill to limit raises for some police and firefighters, Senate Democrats quickly accepted his revisions and sent the bill to the Assembly to consider just before the cap was to expire.

But Speaker Vincent Prieto had already left the Statehouse for the day. His caucus had passed legislation to renew the cap, set to expire April 1, and Christie's conditional veto did not leave much room for negotiation.

With that, Prieto, who became speaker in January, defied the Republican governor, parted ways with Senate President Stephen Sweeney, and sent them a political message: They can't get anything done without the Assembly.

"I said from Day One that I wanted to make sure we were part of the discussion, to be relevant in the conversation, and to really try to have an honest conversation about all the tough issues," Prieto said last week in his Secaucus legislative office.

Prieto insisted that the debate over extending the limit on raises negotiated through arbitration is not about making a point. He said he is negotiating with Christie to break a monthlong impasse.

Yet the tussle, playing out against the backdrop of investigations into lane closures at the George Washington Bridge that have drained some of Christie's political capital, could set the tone for the governor's second term - and Prieto's speakership.

"Speaker Prieto is playing a strong hand," said State Sen. Raymond J. Lesniak (D., Union). "But so is Chris Christie."

Repeatedly criticizing Prieto and the Assembly, the governor has said failure to renew the cap hurts taxpayers by driving up property taxes.

"Christie knows how to seize the moment and draw attention away from his own problems," Lesniak said.

Prieto, a 53-year-old, mustachioed Hudson County Democrat, has not lashed back publicly. His measured approach is more in keeping with his humble beginnings: from a childhood in communist Cuba, to a plumbing business in Union City, to champion of the "Mr. New Jersey" bodybuilding contest.

The youngest of four children, Prieto grew up in a small Cuban town, where clothes and food were rationed: one-quarter of a loaf of bread per person; six ounces of red meat a week, if available; one pair of shoes a year.

"I was born into communism," he said.

At age 10, he and his mother, who worked in a cigar factory, boarded one of the last "Freedom Flights" to the United States in 1971, joining about 265,000 other Cubans who escaped Fidel Castro's rule. His three siblings came to the United States in the 1980s and now live in Miami.

Prieto settled in Union City, close to his grandmother and uncle. He and his mother moved into a one-bedroom, basement apartment. Prieto, now a municipal code official, said: "I definitely know it was an illegal apartment because there was no heat."

He went to school in one of the state's lowest-performing districts and did odd jobs to support his mother, who received food stamps. After attending college for several semesters, Prieto got his plumbing license and opened a plumbing supply store with his brother-in-law.

He went back to college to get his code enforcement technologies and fire technologies licenses. He eventually became the construction code official for Secaucus, where he and his wife, Marlene, had moved in the early 1990s. They raised their two children there.

In his free time, Prieto, who said he was "always a thin, scrawny kid," worked out. The hobby landed him a trophy in 1994, when he won the state bodybuilding competition. The distinction has given him some credibility in Sweeney's eyes.

"I was always thick, and he was always cut," said Sweeney, an ironworker by trade.

Prieto said he did not seek out politics. But when Anthony Impreveduto of Secaucus resigned from the Assembly in 2004 amid a campaign-finance scandal, Hudson County's top political brass tapped Prieto.

"He was an immediate asset to the ticket," said State Sen. Nicholas Sacco (D., Hudson), whom Prieto called a mentor. "He was bilingual; he worked extremely hard."

Apart from an awkward encounter or two - "The first thing that somebody says is, 'Whoa, he's not a lawyer?' " he recalled - Prieto experienced a smooth transition.

After a stint as deputy majority whip, Prieto became chairman of the Budget Committee in 2012 and shared leadership of the Democratic caucus with Speaker Sheila Oliver of Essex County, Majority Leader Louis D. Greenwald of Camden County, and party chair John S. Wisniewski of Middlesex County.

An opportunity arose last fall to pursue the speakership. Oliver had fallen out of favor with some Democrats - including a powerful bloc in South Jersey led by George E. Norcross III - while key players in Hudson, Bergen, and Passaic Counties coalesced around Prieto. (Norcross is the majority owner of The Inquirer.)

Prieto was sworn into the Assembly's top job in January, preserving the North-South division of power, as Sweeney, of Gloucester County, retained leadership of the Senate.

Since the police and firefighter arbitration issue flared in March, Christie has accused Prieto of bowing to special interests that fill Democratic campaign coffers.

The governor says the 2 percent cap on raises awarded through arbitration - enacted in 2010, with a provision to sunset in 2014 - is needed to slow the growth of property taxes. Prieto agrees that the cap is important, but his bill would allow savings achieved through increased employee contributions to pensions and health premiums to go toward bigger raises, among other provisions.

"It was just being mindful that their job is not the same job that you or I do," he said.

Sweeney says he respects Prieto's position. "We as Democrats fight on a regular basis," Sweeney said. "Vinnie feels strongly about it, and he's standing his ground."

Prieto has staked out other politically unpopular positions, such as advocating for an increase in the gas tax to shore up the state's depleted transportation fund.

He also authorized a subpoena-powered investigation into the George Washington Bridge scandal, which critics have denounced as a witch hunt to undermine Christie's presidential ambitions.

That decision, one Democrat said, was not a sure thing. Prieto had to consider: "Do I want to spend [political] capital on this?" said the Democrat, who asked not to be named while discussing private deliberations.

New challenges have emerged, including an $807 million revenue shortfall with just two months left in the fiscal year.

When the shortfall was announced last week, Prieto issued a news release saying: "We're now going to have to roll up our sleeves" to solve the problem.

"I'm not a big sound-bite guy," he said. "We need to put rhetoric and sound bites aside. This is all our problem."