Newark Mayor Cory Booker officially announces his run for the U.S. Senate to fill the seat vacated by the death of Sen. Frank Lautenberg (D-NJ).

Newark Mayor Cory Booker officially announced his candidacy for the U.S. Senate at a news conference in New Jersey on Saturday.

Booker, 44, will run to fill the seat vacated by the death of Sen. Frank Lautenberg, who died on Monday of viral pneumonia.

“Democracy is not a spectator sport,” Booker said at the event. “Now as much as at any time we must bring people together, we must get actually into the complicated, difficult, messy arena and take on the difficult challenges.”

The Democratic primary will be held in August, and Representatives Frank Pallone and Rush Holt are also expected to enter.

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