Mel Evans/AP Photo

Newark Mayor Cory Booker won the Democratic primary today for the special election to fill New Jersey's U.S. Senate seat that is open due to Frank Lautenberg's death in June.

With 46 percent of precincts reporting, Booker beat his opponents by a wide margin, with 59 percent, while his closest challenger Rep. Frank Pallone had 23 percent, followed by Rep. Rush Holt with 13 percent and State Assembly Speaker Sheila Oliver with just 5 percent, according to the Associated Press.

He will face off against Republican businessman Steve Lonegan who beat physician Alieta Eck 80 percent to 20 percent, also with 46 percent of precincts reporting, according to the AP.

The results were not a surprise as Booker, 44, has been the front-runner in the race for months, including the latest poll released last week from Quinnipiac University, which showed 54 percent of likely Democratic voters backed Booker, a 37-point lead over Pallone, who had just 17 percent support. Holt trailed with 15 percent, while Oliver had just 5 percent support.

"He was the frontrunner from the beginning of the race and has an extraordinary level of popularity for a politician, especially as a politician that is the mayor of Newark, being the mayor of a city has rarely been seen as the path of greater political glory, but he has been something of a phenomenon in New Jersey politics," John Weingart, the associate director of the Eagleton Institute of Politics at Rutgers University, told ABC News.

The timing of the primary, when much of the state is enjoying the Jersey Shore, meant turnout was expected to be low and early reporting shows that it was, but did not change the final outcome. There was also heavy rain throughout the state today.

"I think the turnout will be very low for multiple reasons, both the fact there is only one race on the ballot and the scheduling in the summer, and the fact in both parties there is a heavy favorite to win. Particularly on the Democratic side, Holt and Pallone mounted serious, organized challenges with phone banks and some visibility, but you have to have been really motivated to think there would be an outcome other than what has happened," Weingart said.

To fill the vacant seat, Republican Gov. Chris Christie called the Aug. 13 primary and set the special election for Oct. 16, just three weeks ahead of the Nov. 5 general election, when Christie is seeking re-election against Democratic state Sen. Barbara Buono. Democrats accused Christie of wanting to avoid being on the same ballot as Booker, who could attract Democratic turn out. The extra date cost the state millions.

Throughout the campaign, Booker's opponents have tried to portray him as more of a media-attracting celebrity than a public servant, but they have had little traction against the well-known and well-funded Booker, who is thought of as a rising political star. He has also made a name for himself by responding directly to constituents on Twitter and he has enjoyed the support of celebrities like Oprah Winfrey, who held a fundraiser for him last month.

In the first debate of the four Democratic opponents, as well as a campaign video, Holt said he has "never run into a burning building," teasing Booker for his rescue of a neighbor from a house fire last year, which earned him "hero" headlines. Holt added that, unlike Booker he doesn't have "one million Twitter followers" and isn't "friends with Mark Zuckerberg."

It's been a similar refrain, in July the Lautenberg family backed Pallone over Booker and in a clear dig the family wrote that Pallone most reflects Lautenberg's values including his focus on being a "workhorse, not a show horse."

"Frank Pallone, like our Frank, will put in the hours and hard work necessary to fight for New Jersey in the Senate. And Frank Pallone knows that gimmicks and celebrity status won't get you very far in the real battles that Democrats face in the future," the letter said.

There were clear tensions between Lautenberg and Booker before his death. Most notably, Booker announced his intentions to seriously consider a run before the 89-year-old Democratic senator had announced whether he would seek another term himself.

That didn't sit well with Lautenberg and he made it clear in no uncertain terms, saying Booker may be "entitled" to his seat, but comparing him to one of his badly behaved children.

"I have four children," Lautenberg told the Philadelphia Inquirer in January. "I love each one of them. I can't tell you that one of them wasn't occasionally disrespectful, so I gave them a spanking and everything was OK."

Booker has also been able to maintain his lead despite several unflattering stories recently, including a front-page New York Times article last week that detailed Booker raising $1.7 million from wealthy tech executives for a nascent tech startup, Waywire, as well as his close involvement with Silicon Valley executives. The story detailed Booker's involvement in soliciting donations for the venture from wealthy donors, including Winfrey.

But, none of the criticism whether about Booker's political credibility or the ethics allegations ever seemed to stick.

Booker will need to run again just next year for the full six-year term. It is then that Weingart said these issues could pop if a Democrat or Republican decides to challenge him.

"It remains to be see if any of these (stories) will have an impact on this year's race," Weingart said, noting it's likely Lonegan has "attacks prepared" and will have a "fair amount of funding."

"If any of these questions about his financial dealings have started a theme of concern for people, it may have more of an affect on the 2014 race and perhaps encourage candidates to challenge him that may otherwise think he is invincible," Weingart said.

Booker is the first African-American to be nominated by a major party for a statewide office in New Jersey, something Weingart notes has been hardly mentioned in the race.

"It's noteworthy that it is not noteworthy," Weingart said. "I don't know if it speaks to him or the state of race relations, but that would have been a big story various times in the past, but now it is just a footnote to this election."

Booker will face off against Lonegan on October 16. He is heavily favored in that race as well. That same Quinnipiac poll showed Booker leading Lonegan 54 to 29 percent in a general election face off.