A tumultuous Senate contest marked by the stunning, 11th-hour withdrawal of Sen. Robert G. Torricelli (D) culminated tonight in one of the Democratic Party's few bright spots -- a victory by retired three-term senator Frank R. Lautenberg, Torricelli's replacement.

Introduced to a cheering crowd as "New Jersey's senator for life," Lautenberg called his victory "a mandate" for the liberal social agenda on which he ran -- tougher gun control, abortion rights and environmental protections -- and pledged to fight with New Jersey's soon-to-be senior senator, Jon S. Corzine (D), for measures to stimulate the flagging national economy.

Republican Doug Forrester, 48, a multimillionaire businessman and political novice only five weeks ago was leading Torricelli in the polls by double digits. But Forrester's lead evaporated with the scandal-tainted Torricelli's exit, and Lautenberg steadily reassembled the coalition of Democrats and independents that has elected Democrats in New Jersey in every U.S. Senate race since 1978.

With 97 percent of precincts' results reported, Lautenberg led Forrester 54 to 44 percent.

"Doug Forrester wanted Torricelli out of there," a relaxed and smiling Lautenberg said today during a pre-victory lunch with his children and grandchildren at a diner. "Then he got his wish and he wanted him back!"

That statement effectively sums up New Jersey's bizarre and chaotic chapter of the 2002 battle for the Senate. National strategists in both parties initially assumed the state was a sure bet for the Democrats. Then the Senate Select Committee on Ethics "severely admonished" Torricelli for accepting lavish gifts from a now-imprisoned campaign donor. Forrester -- whose only other race came 20 years ago, for mayor of suburban West Windsor -- opened a wide lead with a largely self-financed campaign as "the guy running against Bob Torricelli."

But Forrester accomplished his stated goal of retiring Torricelli about five weeks too early. Torricelli withdrew on Sept. 30, two weeks after a statutory deadline for making ballot changes, and the Democrats replaced him with Lautenberg, 78. The New Jersey Supreme Court ruled unanimously that the deadline could be waived, and Republicans went to the U.S. Supreme Court, trying in vain to stop them.

Forrester attempted to tarnish his new opponent as a product of the "Torricelli-Lautenberg" machine and accused him of being soft on defense, particularly for his 1991 vote against the Persian Gulf War resolution. Republicans called him too old, saying he was "out of step" as war loomed with Iraq, and even branding him "incoherent."

But none of it stuck. Lautenberg ended up saying he supports giving President Bush authority to attack Iraq now and criticized Forrester as being well to the right of New Jersey on the social issues that favor Democrats in this moderate-to-liberal state.

As to whether he was too old, a jubilant Lautenberg told his victory crowd -- with exaggerated sarcasm -- "Let me let you in on a secret: It's past my bedtime, I had a glass of warm milk and I'm feeling very springy." Amid loud cheers and laughter, he roared, "Let them try that again!"

When Lautenberg mentioned Forrester's name, the crowd booed. He reproved them in statesmanlike fashion: "We can afford to, and we want to, be nice. He is, after all, a constituent of mine now."

Organized labor sent 11,000 men and women to help Democrats get out the vote, and Lautenberg pledged tonight to be loyal to them once in office.

With a majority of its voters registered in neither party, New Jersey has been closely watched nationally as the prototypical swing state. But for a decade now, it has been voting increasingly Democratic -- for Bill Clinton in 1992 and 1996 and for Al Gore over George W. Bush in 2000 by a lopsided 56 to 40 percent.

"The returns show that you've got a bunch of shadow Democrats masquerading as independents in New Jersey," said Rutgers University political scientist Ross K. Baker.

Former senator Frank R. Lautenberg ran for the Senate seat that had been held by Democrat Robert G. Torricelli, who withdrew.