New Jersey Democrat Cory Booker has raised $4.6 million in the past three months as he seeks a U.S. Senate seat in a special election.

Booker's campaign was the first to announce on Thursday a second-quarter fundraising total. Candidates have until Monday to file fundraising figures with federal officials for the quarter that ended June 30.

The Newark mayor and three others are seeking the party's nomination to fill the last year of Sen. Frank Lautenberg's term. Lautenberg died last month. Two Republicans are also running in Aug. 13 primaries. The general election is Oct. 16, and another election for a full six-year term will be held next year.

Recent voter polls show Booker far outpacing his lesser-known Democratic rivals -- Reps. Frank Pallone and Rush Holt and Assembly Speaker Sheila Oliver. Pallone had more money -- about $3 million to Booker's $1.9 million -- as of the end of March.

Booker, the two-term mayor of Newark, the state's largest city, announced his intent to run for Senate in December, then created a federal fundraising account allowing him to raise money for a Senate campaign.

From March through June, he received more than 7,000 contributions, a majority from out-of-state donors. Facebook founder Mark Zuckerberg, who has given Newark schools a $100 million matching grant, recently hosted a fundraiser for Booker in California.

Oliver, whose entry into the Senate campaign surprised some, sent an email to potential donors this week seeking contributions of $10, $25 or more to help propel her grassroots campaign. She will file her first federal fundraising report.

A Quinnipiac University poll released this week showed Booker with a commanding lead of 52 percent with five weeks before the primary. The poll showed Pallone with 10 percent, Holt with 8 percent and Oliver with 3 percent. A quarter of those surveyed were undecided. The poll showed winning support for each of the four Democrats over the presumptive Republican nominee, Steve Lonegan, although only Booker had a double-digit margin.

New Jersey has not elected a Republican to the U.S. Senate in more than 40 years.

Gov. Chris Christie appointed fellow Republican Jeffrey Chiesa to fill the seat until the election. Chiesa, Christie's former attorney general, isn't running for the unexpired term.


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