2014, adding intrigue to his political future and that of 88-year-old fellow Democrat Frank Lautenberg, who currently holds the seat.
Booker filed paperwork with the Federal Election Commission on Tuesday that allows him to raise money for a Senate campaign. The prolific social media user has not tweeted about it or made any public announcements about the filing, and his staff did not return a call to The Associated Press on Friday, but it came as no surprise.
Booker, perhaps New Jersey's highest-profile Democratic politician, last month turned down the party leaders who wanted to see him challenge incumbent Chris Christie in the 2013 gubernatorial election. Instead, Booker said, he was looking at a run for the Senate next year.
His interest puts pressure on Lautenberg, the oldest member of the Senate.
When Booker said he might run for the seat, he praised Lautenberg for his service, but said he had not spoken with him about his plans. Lautenberg's spokesman, Caley Gray, said in a statement Friday that Lautenberg has not decided whether to seek re-election next year.
The Stanford-educated Booker has steadily built his national profile over the last six years as Newark's mayor. An adept social media user with 1.3 million Twitter followers, Booker is known for responding to constituent complaints electronically and last year took on a tweeted challenge to live on food stamps for a week.
Lautenberg, who was treated for cancer three years ago, missed the Jan. 1 vote on the "fiscal cliff" legislation because of the flu but has never given any indication that he would like to retire.
And Booker has not said whether he would be willing to take on Lautenberg in a primary run if the senator tries to keep his seat.
In 2008, New Jersey's Democratic establishment decided that Lautenberg was not too old to serve.
U.S. Rep. Rob Andrews challenged him a primary. Most of the state's Democratic leaders stood with Lautenberg, who won handily then retained his seat in the general election.
U.S. Rep. Frank Pallone, a Democrat from central New Jersey, has also expressed interest in Lautenberg's seat. But on Friday, his spokesman, Raymond Zaccaro, said Pallone's not thinking about whether he'll run in the election, which is 22 months away, but instead is focused solely on recovery from Superstorm Sandy, which hit his district hard.
Booker was elected mayor of Newark in 2006 with 72 percent of the vote, four years after narrowly losing a bruising battle against longtime Mayor Sharpe James. The race was chronicled in the 2005 documentary "Street Fight." He was re-elected in 2010 with about 60 percent of the vote.
During Superstorm Sandy, he invited residents to charge their cellphones at his house. In April, he let the world know through Twitter that he rushed into his neighbor's house and rescued her from a fire. During a snowstorm, he helped shovel people out.
Booker's critics say he spends too much time rubbing elbows with celebrities and not enough fixing his city.
But in one case, his high-profile connections paid off. In 2010, after sitting with Booker at a dinner, Facebook founder Mark Zuckerberg agreed to donate $100 million to try to improve education in the city. Booker also boasts of a more stable city budget and of downtown redevelopment on his watch.
A Rhodes Scholar who grew up in suburban Harrington Park, N.J., Booker is the son of civil rights activists who were among the first black executives at IBM. He got his law degree from Yale Law School, then moved to one of Newark's most notoriously violent housing projects.
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