Cory Booker may be a Democratic Party star; he may have a 40-point lead over rivals in the polls; he may have 1.4 million followers on Twitter and a name familiar to every voter up and down the Garden State and across much of the country — but the special election for U.S. Senate this fall isn't his for the taking.

New Jersey Democrats involved in and following the race to fill the late Sen. Frank Lautenberg say the Newark mayor is the clear favorite, but that his opponents will work to expose a number of weak points in his narrative to take down the national political celebrity.

Since Gov. Chris Christie announced Tuesday afternoon that a special election would take place fall — with a primary race in August, and a general in October — candidates like Booker have been scrambling to put their campaigns into high-gear, and collect the 1,000 signatures required by Monday to get their names onto the primary ballot. Booker, along with Democratic Reps. Frank Pallone and Rush Holt, has been circulating petitions for signatures. For now, only Holt has made his candidacy official; Booker will announce Saturday at an event in Newark, and Pallone is expected to launch his bid later this weekend, according to sources in both camps. (There is only one declared Republican candidate so far, Steve Lonegan, the former mayor of Bogota — but the primary, not the general, will likely determine New Jersey's next senator.)

New Jersey political insiders said Democratic competitors will seize on the narratives that have persisted around Booker for years — that he spends too much time outside of New Jersey; that he is more popular outside the state than inside; that his record in Newark can't hold up to scrutiny — and that they play up their longstanding relationships with the state party apparatus, which Booker has been known to challenge.

Before Lautenberg's death — when the race to fill his seat was still slated for November 2014 — polling showed Booker led the two congressman in a potential Democratic primary by a hefty margin: with 50 percent of respondents voting for Booker; seven percent for Holt; and just four percent for Pallone.

Booker, poll numbers aside, is far from untouchable — particularly in New Jersey, where, as one state operative observed, "nothing is inevitable." Below are four of the central strategies in the campaign to take down Booker, as described to BuzzFeed by campaign strategists, political observers, party officials, and Democratic operatives in New Jersey.

Cast him as a party outsider

Booker first announced he would run for Lautenberg's senate seat last December, two months before Lautenberg announced that he would retire at the end of his fifth term.

New Jersey Democrats didn't like that math: Booker couldn't have waited for Lautenberg to bow out before saying he wanted to run for senate? The move roiled Lautenberg loyalists, and Lautenberg himself, compounding Democrats' frustration that Booker had not run for governor. He had been, it was widely felt, the only candidate who could have given Christie a run for his money in 2013.

"His announcement was viewed as stepping on Lautenberg's toes without bringing the country and state party into the fold," said Brigid Harrison, a political science professor at Montclair State University, and a close observer of state politics.

"It was viewed as being a little politically expedient and premature, but I don't know that the Lautenberg resentment is going to carry over," Harrison said, adding that what was more worrisome for Booker is the "disappointment Democrats felt when he didn't challenge Christie."

In a state where county party "bosses" have far-reaching political sway, Booker is already behind in fostering relationships with state party leaders, and the New Jersey Democratic establishment. He's viewed by many as the antithesis to a team player.

In a typical primary election, county power brokers have the power to award a candidate the "party line," the most favorable position on a primary ballot. In the case of the 2012 election, for example, candidates on the party line would have appeared beneath President Obama and incumbent Sen. Bob Menendez. But in the senate race this fall, the influential party line will hold less sway, as only special election candidates will appear on the August primary ballot.

"The line doesn't matter as much this time, though even if you're endorsed on the county line, you have a stamp of approval," said a state Democratic operative with ties to the race.

One New Jersey Democratic strategist involved in the special election race said that not many state leaders "are hearing directly from [Booker]; they're hearing from his staff, but not him."

"His biggest obstacle is that he has not developed the county-level political connections that are really important in New Jersey politics," said Harrison. "Pallone has strong connections in the county organizations, and if he's able to use his influence to get endorsed by the county chairs, that carries some measure of weight in a typical primary."

Pallone has "consistently tried to keep a solid relationship with the powers that be within the state party," Harrison added.

Doug Muzzio, a Baruch College political science professor and longtime observer of New Jersey politics, said those relationships could help Pallone quite a bit this fall. "It matters. Those organizations have some muscle to them," he said, but added, "Does it mean that you win if you've got it? No."

State intra-party politics haven't held Booker back in the past, either: He built his political career on challenging incumbents, first in an improbable city council win against four-term incumbent George Branch in 1998; and again in 2002, when he tried and failed to unseat Sharpe James, a corrupt mayor who held Newark city hall for two decades, before Booker finally beat him four years later.

Play up the self-promoting "absentee mayor" caricature

Ahead of his senate run, Booker's campaign office released a financial disclosure form, the filing required of candidates running for senate. But his office also sent reporters four other documents detailing Booker's earnings from paid speeches at colleges, corporations, and non-profits across 32 states over the past five years. The speeches — he has given 90 in total since 2008 — earned Booker $1.3 million, about three quarters of which he gave to charity, according to his office.

The document dump, not required by any campaign finance regulations, appeared to address the persistent line of attack on Booker: that he spends too much time outside of Newark engaging in activities that amount to nothing more than self-promotion. The paid speeches, the interviews on cable news shows, the technology conferences — Booker's level of national prominence can seem improbable for a city mayor.

Last summer, a Star-Ledger review of 18 months worth of public documents and news reporters found that Booker had spent over 21 percent of his time out of town. The article dubbed him the "absentee mayor."

It's a title that could hang over Booker this fall if a rival like Pallone or Holt tries to push the issue to the fore of the campaign.

"The big thing will be hitting him on the 'absentee mayor' stuff," said a Democratic operative involved in the race. "He's gotten a lot of business into the city by going around the country being a cheerleader for Newark, but there's a way to make it a negative too."

"Booker's biggest thing is that he's a rock star. People know him because he's on Bill Maher's show, and he tweets, but those people aren't necessarily New Jersey Democratic voters who will come out in a primary in August," the operative added, noting that 70 percent of Booker's first-quarter senate contributions came from outside the state, according to a Philadelphia Inquirer review of Federal Election Committee reports.

If Pallone and Holt want to move the polls back in their direction, said Muzzio, they'll have to go on the offensive, and fast. "Clearly, those attacks will be the test," he said. "You can go positive, but you've got to go negative if you want to take Booker down. You've got to say, 'This is a show-horse. Not a work-horse.'"

Earlier this year, when Lautenberg was waging cold war over the way Booker had laid claim to his senate seat, the show-horse critique was one he turned to on more than one occasion. In a speech at a New Jersey Chamber of Commerce dinner in Washington, Lautenberg noted that Booker had skipped the event. "I'm disappointed that Cory Booker couldn't be here tonight. I'd think that spending time out of the city was one of his favorite activities," he said. "Perhaps we were too close to Newark."

Point to Booker's failures in Newark

When The New York Times took a hard look at his seven-year record as mayor of Newark, Booker called the piece "just frustrating as heck."

Although Booker suggested at the time that the article had misrepresented his management of Newark city hall — he and his staff even crafted a rebuttal to send to another news outlet — it certainly won't be the last time Booker has to defend his performance as mayor.

The city, New Jersey's largest, has shown marked improvement in areas over the last seven years: population has increased for the first time in six decades, and crime has decreased broadly, with a 17 percent decrease in the homicide rate since Booker took office in 2006.

But with a significant spike in violence from 2011 to 2012, Newark still ranks 20th, behind Nashville and Philadelphia, on last year's Federal Bureau of Investigation list of America's most dangerous cities. Earlier in his tenure, Booker also laid off more than 600 public workers, and 163 police officers, an unpopular decision which he still remembers as "painful." (Booker, though, announced earlier this year that he would hire back 50 officers.)

According to a poll published in the Star-Ledger earlier this year, Booker is well liked within his city: Seventy percent of likely Newark voters have a favorable opinion of him, and 65 percent approve of his performance as mayor.

But one a strategist connected to an opposing campaign said one weak spot in Booker's campaign would be "the fact that his record in Newark is even debatable," the source said. "You look at Pallone and Holt and you see a proven record in Washington, not to mention a voting record."

As mayor of a city, Booker has managerial experience that very well may appeal to voters, but Pallone and Holt have both voted on a range of economic, social, and foreign issues on the floor of the House, providing voters a clear sense of where both candidates stand on national policy.

Rival candidates could also seize on Booker's strained relationship with state teachers unions, as well as his support for charter schools, which are championed by the same hedge fund and Wall Street communities that have financed Booker for years.

"That's what makes us least comfortable," said Steve Phillips, a progressive fundraiser whose political action committee has vowed to raise $1 to $2 million for Booker. "I understand the complexities of trying to do something for lower-income kids in a political bureaucracy, but if I could wave my magic wand, I wouldn't want him as close to the hedge fund folks as he is."

Take advantage of the shorter race

The other factor at play in this race is time, state operatives say. When the clock gets moved forward by more than a year — the primary for the race that should have been held in 2014 is now just 66 days away — even the presumed leaders of the pack find themselves scrambling.

"None of the candidates have established a real coherent message yet, because they didn't expect to thrown into this," said Muzzio. "There is no organization, and there are a lot of unknowns."

Booker was just this spring beginning to put the infrastructure in place for his campaign. In March, he hired a communications director, Kevin Griffis; and in April, he brought in his finance director, Lauren Dikis. The campaign staff remains a small operation — Griffis and Dikis are joined by a political director, and finance staffers, but not many others. The campaign will have to accelerate the hiring process in the coming days and weeks, aides say.

The mayor will also have to speed up his fundraising efforts. According to FEC filings, he has $1.6 million in cash on hand, as of March 31, compared to Pallone's $3.7 million. Holt, meanwhile, has just $790,000. The most recent records available, though, do not include a fundraising swing Booker took through California, where he headlined a private Los Angeles reception, where major motion-picture producer Jerry Weintraub hosted and Democratic kingmaker Jeffrey Katzenberg was a big-name attendee.

But operatives inside the state say both Pallone and Holt can rake in the cash, too — and may be able to compete with Booker now that time is more limited.

Holt, who has had to run much more competitive reelection races than Pallone, may better adapt to the competitive field of the special election. The former physicist's first successful race in 1998 was not one many believed he could win — he did, but by just under three percent of the vote. More recently, he held his seat in 2010 in a particularly tough race against Republican Scott Sipprelle, an independently wealth candidate who financed much of his own campaign.

"Holt is the only one who has won a race that no one said he could win," said one state Democratic strategist. "Pallone has never had a tough race. There's a difference between throwing elbows and kicking someone in the nuts, and Holt knows how to do that. We'll see if Pallone does," the source said.

With just weeks until the primary, elbows will be flying earlier, and candidates will be angling to get on the air in the expensive New York City and Philadelphia media markets — New Jersey doesn't have its own — as soon as they can afford it. Whether Pallone or Holt can throw enough elbows to edge Booker out in just under 70 days remains an open question.

But in a sprint to the finish, "it's all possible," said Muzzio. "Booker can lose it. Holt and Pallone are substantial guys, and in a short race, any number of variables can come into play."