Back in the summer, few in New Jersey raised an eyebrow when the police commissioner in Newark reporting to Mayor Cory A. Booker suddenly imposed a policy refusing to assist federal officials trying to deport illegal immigrants.
In other states, the move could have been political kryptonite for Mr. Booker, but not in New Jersey, where he went on to win the Democratic nomination for the state’s U.S. Senate seat, and appears headed for a victory over Republican Steve Lonegan in next week’s special election.
Mr. Lonegan, a small-business owner and former mayor of the Bergen County borough of Bogota, has struggled to make charges stick against his better-known and better-funded opponent. He has lodged attacks against Mr. Booker for spending time at out-of-state fundraisers, his ties to President Obama, and even a brief foray to criticize the Newark mayor for the immigration policy.
Polls show the race tightening but seemingly well beyond the Republican’s reach. A Quinnipiac University Poll released Wednesday gave Mr. Booker a 12 percentage-point lead and showed that the hottest issue of the race — Mr. Booker’s Twitter relationship with an attractive stripper — hasn’t hurt him.
“From the public standpoint, it is not all that clear what the issues are other than Lonegan is anti-government and supportive of the government shutdown and that Booker is saying that the government can do good things,” said David P. Redlawsk, director of the Eagleton Center for Public Interest Polling at Rutgers University in New Jersey.
The seat opened this year with the death of Sen. Frank R. Lautenberg, a Democrat and the last remaining World War II veteran to serve in the upper chamber.
New Jersey Gov. Chris Christie, a Republican, tapped Jeffrey S. Chiesa, the state’s Republican attorney general, to the seat, and set up an Oct. 16 special election to fill out the rest of Mr. Lautenberg’s term, which ends next year. Whoever wins the contest will have to decide whether to defend the seat in the 2014 election.
With polls narrowing, Democrats and other Booker allies are sending in financial reinforcements. New York Mayor Michael R. Bloomberg announced this week his Independence USA political action committee was bankrolling a campaign ad for Mr. Booker.
“The assumption remains that Cory Booker is likely to win this, though he may not win by the kind of margin that was earlier anticipated and that most people believe that is because he has not run much of a campaign,” Mr. Redlawsk said.
Jennifer Duffy, of the Cook Political Report, said the seat is “solid Democratic.”
“While a couple of reliable polls have shown some closure, Booker is still above 50 percent, and has a considerably greater presence on television, which is critical in New Jersey,” Ms. Duffy said.
Rick Shaftan, a Lonegan spokesman, said the polls are misleading because turnout is unpredictable in special elections.
“We are in a neck-and-neck race,” said Rick Shaftan, a Lonegan spokesman. “This is a turnout race.”
Mr. Booker cruised to victory in the Democratic primary and has spent a lot of time outside the state at fundraisers hosted by the likes of Matt Damon and Oprah Winfrey — opening him up to criticism that he is more interested in his national celebrity than in governance.