It’s man vs. the machine: Newark Mayor Cory Booker and Rep. Frank Pallone Jr. are on track to have a New Jersey-style knockout primary for the Democratic Senate nod in 2014.

“It changes the landscape,” Pallone said minutes after Sen. Frank R. Lautenberg’s retirement announcement. “I’ve always been interested in the Senate, and I’m going to continue to explore it.”

This brewing political battle would match an outsider with an army of Twitter followers, wealthy celebrity connections and television news fame against a congressman who has spent years currying favor with the state establishment to run for this very seat.

Immediately, national Democrats predicted Booker would have an easy walk to the nomination. But some Garden State operatives are dubious.

Booker upset party elders when he announced his exploratory committee in mid-December. Many Lautenberg loyalists are furious with him for not being patient and allowing Lautenberg a graceful exit. In the end, Booker only needed to wait two months to make his move.

Meanwhile, Pallone bent over backward to take the opposite approach as he quietly prepared for a run.

“Today’s about Frank Lautenberg,” Pallone repeated in the interview. He declined to discuss an official announcement or future strategy.

But there’s also a practical reason the New Jersey Democratic establishment blessing is important. A county Democratic Party’s endorsement gives a candidate preferential treatment on the ballot, known locally as “the line.”

“They can’t vote for you if they can’t find you [on the ballot],” said one Washington Democratic strategist who is familiar with New Jersey politics.

It is almost impossible to win a primary without that advantage. Sources say Pallone has quietly put everything into place for a longtime congressman to leverage the line.

Meanwhile, many local Democrats wonder whether Booker has put the line in jeopardy with his eagerness. Several influential county chairmen contacted by CQ Roll Call this week said Booker has made serious miscalculations in the past few weeks.

But the same top Democrats hailed Booker’s appearances around the state, including his capacity to fundraise, taking the pressure off party leadership to bring in bucks.

“He didn’t help himself, but he’s got a lot of other things going for him that may make up for it by next year,” one county chairman said.

Booker’s brand of politics is unique, and his national status might test the efficacy of the line. Plus, public polls show he starts the race with a big advantage.

Booker had a commanding lead over a field that included Lautenberg, Pallone, state Senate President Steve Sweeney and state Assembly Speaker Sheila Oliver in a Monmouth University/Asbury Park Press poll released Thursday.

Pallone registered in the single digits in the survey. But early polls like these are typically a result of name identification.

In any case, local Democrats treat Pallone as a serious contender. Democrats describe his work ethic with affection. Sources say he has been a familiar face at events all over New Jersey for years.

He’s represented the Garden State in Congress since 1989, which means he has represented four different versions of his House district that covers a large swath of the state.

Pallone also has $3.4 million in his campaign account. That will go far in one of the most expensive statewide media markets in the country. New Jersey includes both the New York City and Philadelphia media markets. None of the other often-mentioned contenders for the Democratic primary — Sweeney and Oliver — responded to requests for comment as of press time.

But there could be another candidate from the delegation. Aside from Pallone, other New Jersey members have long coveted the seat.

Republican Rep. Scott Garrett declined to comment on whether he will run for the Senate, but he did note the state’s expensive media markets.

Television personality Geraldo Rivera has also expressed interest in running as a Republican, but few strategists take the idea seriously.

In any case, Lautenberg’s shadow over the primary to succeed him will loom large. Both Booker and Pallone were quick to praise Lautenberg on Thursday.

Pallone called him “an extraordinary leader in the U.S. Senate, and he has served as a moral guidepost on so many critical issues.”

“On a personal note, Sen. Lautenberg has been a strong model of leadership and service to me since before I even considered entering elected office,” Booker said.

Lautenberg declined to say whether he would endorse anyone in the primary in a brief interview at the Capitol. When asked whether Booker had reached out to him following his announcement, it was clear the bad blood persists between the two Democrats.

“He doesn’t have my number,” Lautenberg replied.

Meredith Shiner, Joshua Miller and Steven T. Dennis contributed to this report.