The sharpest exchanges of New Jersey's brief Senate race arrived Thursday night.

U.S. Reps. Frank Pallone and Rush Holt used the second and final Democratic debate before Tuesday's primary to launch their most pointed, aggressive attacks on Newark Mayor Cory Booker, questioning the front-runner's liberal credentials, his dedication to his job, and his ties to big business.

The normally laid-back Pallone was most aggressive, repeatedly criticizing Booker's work in Newark.

"I don't know how the mayor expects that he's going to get things done because he's always been aligned with Wall Street and Bain Capital and all these special-interest groups," Pallone said. "I'm the person who's trying to help working families."

At the end of a night that saw his name battered for most of an hour, Booker responded by saying that after more than 40 years combined in Washington, Holt and Pallone are part of a "broken" political system and "haven't got it done."

The three candidates, along with Assembly Speaker Sheila Oliver, clashed at the WBGO radio studio in Newark. Oliver was less involved in the political cross fire.

Holt set the tone, using his opening statement to tout his liberal record and challenge Booker's broad statements about unifying Washington.

"Listen to see which candidate offers this kind of progressive vision and which candidate offers vague rhetoric about coming together in some kind of new politics," Holt said.

When Booker said a carbon tax to curb pollution should "be on the table," Holt shot back: "There goes Cory again."

"He says we've got to come together in a new way of thinking, or something," Holt said. "Let's get specific here. Our positions shouldn't be top secret. Are you for it or are you against it?"

At one point Booker held his palms up, seemingly stunned by the ferocity of fellow Democrats.

"If you're happy with what you're getting from Washington, stick with what's in Washington now," Booker said. "I don't think we need more Washington experience. We need a different kind of experience in Washington."

With a faster-moving format and focus on domestic issues, the exchanges were a stark shift from Monday's sleepy first debate. Thursday's event, televised on News 12 New Jersey, was the last formal opportunity for the candidates to hit Booker, the heavy favorite with huge leads in polls, popularity, and fund-raising.

His advantages are substantial, but the congressmen arrived with their elbows out. Booker was staggered for the first time in the campaign.

He has long received campaign support from Wall Street, and in last year's presidential race he defended Bain against attacks from President Obama - drawing ire from the left.

Pallone attacked Booker's travels outside of Newark, a sore point for the mayor's vocal critics. It was the first time in the race a Democrat took aim at his work as mayor.

"I don't know how he can say he's hands-on when he's not even there," Pallone said, asserting that he had to intervene to help a nonprofit group that couldn't get aid from the mayor. "He's not doing his job."

He also shot back at the mayor's assertion that Congress is broken.

"If you have experience . . . you can actually get things done," Pallone said.

At several points Pallone brought up Waywire, an Internet start-up that Booker has an ownership stake in. The New York Times revealed this week that the company has received financial help from Silicon Valley moguls, raising questions about Booker's connections to tech giants who have potentially helped him get rich. Booker's ownership stake is worth $1 million to $5 million, according to his disclosure forms.

Pallone said Booker is "running around the country basically putting together this Internet start-up rather than dealing with the problems of Newark."

Holt said Booker "has some explaining to do" about "running this company while he was supposedly a full-time mayor."

And he accused Booker of forwarding "Republican politics" for telling a newspaper that he would consider some reductions in Social Security benefits for younger workers.

Booker said that his rivals were "muddling my record" and that he would stand against "anything that's going to reduce benefits."

After trying to deflect the attacks, Booker dug back at his opponents.

"It's unfortunate that Congressman Pallone wants to talk about me tonight more than the issues and what's affecting you," he said to the camera.

As for his travel, he said, "I'll never apologize for bringing a record amount of investment to our city."

He did not address the Waywire controversy, but pointed out that Pallone and Holt voted for the Patriot Act, which they now criticize, and for a bill that loosened bank regulations.

"It's obvious that my opponents came to attack me," he said.

He concluded by saying: "It's time for us to put new energy and change agents in Washington."

Booker did not speak to reporters after the debate, going instead to a campaign event.

In her opening statement, Oliver pointed to her experience at all levels of state and local government.

"There is no facet of public policy that I have not been engaged in. . . . I think that I am well prepared to be your U.S. senator and want to be the first woman from New Jersey to be a U.S. senator," Oliver said.

She promoted her work on statewide issues as leader of the Assembly.

"The next U.S. senator has to focus on what is important to communities across a broad spectrum," she said.

The winner of the Democratic primary will face either conservative leader Steve Lonegan or physician Alieta Eck, who are running in the Republican race. The general election is Oct. 16.

Contact Jonathan Tamari at jtamari@phillynews.com or follow on Twitter @JonathanTamari. Read his blog, "Capitol Inq," at www.inquirer.com/CapitolInq.
Inquirer staff writer Andrew Seidman contributed to this article.