“This is about what kind of politics prevails in Newark at this point,” said Clement A. Price, a professor at Rutgers and the city’s official historian, who has not taken sides in the contest. “Is it a political culture that wants to ‘take back Newark,’ return to a Newark Cory Booker usurped, or will the city move forward, in part as a result of the kind of paradigm we saw when Cory came to town?”

Street confrontations and an onslaught of ads and mailings between the campaigns have made the 2002 race between Mr. Booker and Mayor Sharpe James, chronicled in a documentary called “Street Fight,” seem civil by comparison. Last April, Mr. Baraka and Amiri Baraka Jr., his brother, abruptly arrived at Mr. Jeffries’s house, arguing with him to get out of the race. Amiri Jr. was videotaped in January screaming at volunteers putting up signs for Mr. Jeffries, warning them he would “destroy our community.” Last month, two campaign workers for Mr. Jeffries were arrested and accused of setting fire to Mr. Baraka’s campaign bus in February. And the office of Mr. Jeffries’s campaign manager was vandalized.

Independent groups have spent more than $3.5 million on a series of television ads, seeing this as a proxy war over education, between those who back charter schools, including Gov. Chris Christie, and unions that oppose them.

“They’re coming. From Wall Street. From Trenton. To sell us Shavar Jeffries,” warned one ad by a coalition of unions backing Mr. Baraka. “Chris Christie’s allies and the Wall Street hedge fund types have an agenda. Shut down Newark public schools. Shut out parents. And destroy our schools for their personal profit.”

“Newark is not for sale,” another ad declares — an echo of the argument made against Mr. Booker in 2002 by Mayor James, who went to federal prison and is now supporting Mr. Baraka. (His son is running on the same ticket for Municipal Council.)

Mr. Jeffries and the groups backing him, largely education reform groups that supported Mr. Booker, have hammered Mr. Baraka on crime, noting that murders in the South Ward, which he represents, have risen 70 percent since he joined the council in 2010. Anonymous mailings circulate news stories reporting that Mr. Baraka wrote letters seeking leniency for one of the city’s most notorious gang leaders. “Who is he fighting for?” one asked. “Are gang leaders our kids’ heroes?”