Republican gubernatorial candidates mixed it up over illegal immigration, the tone of the state Supreme Court, and cutting taxes in a three-way debate on New Jersey 101.5 FM radio last night.

Although analysts predicted that the establishment Republicans' favorite, former U.S. Attorney Christopher J. Christie, would have an easy walk in Tuesday's primary, he has received stiff opposition from Steve Lonegan, the former mayor of Bogota in Bergen County. Two recent polls put Christie substantially ahead of Lonegan, but no one knows for sure how many voters Lonegan's grassroots efforts will draw to the polls next week.

Last night's debate was a continuation of the two front-runners' increasingly caustic struggle to influence Republican voters. A third candidate, Republican Assemblyman Rick Merkt, of Morris County, also participated.

Lonegan took the first shot, saying that "the most liberal state Supreme Court chief justice is Stuart Rabner, and my opponent Chris Christie was the chief public fan, proponent, supporter, and endorser of Stuart Rabner in New Jersey. It's hard to think that Chris is going to take a hard line when he's so close to a man who's arguably the most liberal chief justice of a supreme court in the United States of America."

Christie responded: "Steve's really funny. He really is. He thinks if he continues to say something long enough it's true. . . . He's made the determination that Stuart Rabner is the most liberal justice in the United States. Quite a claim, but something we're used to hearing from Steve."

Lonegan did not explain how he came to that conclusion.

Rabner served with Christie in the U.S. Attorney's Office and was appointed to the bench by Democratic Gov. Corzine in 2007.

Christie then went on the offensive by raising an embarrassing incident in answering a listener's question about curtailing illegal immigration in New Jersey.

In 2007, Lonegan was in a dust-up with authorities after local police arrested two men he had hired to work on political signs, charging they were illegal immigrants.

Lonegan said last night that he opposed the idea of making employers responsible for verifying whether employees were legal immigrants, to which Christie said, "I can understand why Steve doesn't want to have it."

Lonegan retorted, "You know what, Chris, you don't understand. You don't understand what it is to create a job. I ran a business for 25 years. I employed 50, 60, 70 people. I know what it is to create jobs."

Christie said, "And you know what it is to hire illegal immigrants."

Merkt called them both "dishonest" when it came to their plans to cut taxes because he said both houses of the legislature are controlled by Democrats unlikely to listen to a Republican governor.

"You can't make those kinds of promises credibly without getting the Legislature to go along," said Merkt, an assemblyman for a decade.

Christie said that legislators would be forced to bend to the will of the people, which Merkt called "totally naive."

Merkt summed up his position by saying, "I'm telling you right now: Guys, you're dreaming."

On other issues, Merkt and Lonegan said the state would be better off without a unionized workforce. Christie said he wanted either unionized state workers or employees working under a civil-service system, but not both, which sometimes have differing rules.

Merkt and Lonegan said they would do away with property-tax rebates and equalize school funding in all districts to lower property taxes. Christie said he would keep the rebate program.

Though a primary candidate, Merkt was unable to raise enough money to qualify for state matching funds and was not included in state-sponsored televised debates. A jogger, he has literally run through the state's 566 municipalities on his way to a spot in last night's debate.

Corzine, too, is running in Tuesday's primary but has marginal opposition. His standing in public opinion polls has been low, and for months Christie has been running ahead of him in a hypothetical general-election matchup.

Corzine's campaign began running television commercials a week ago.

Unlike the Republicans, Corzine has said he would not participate in the state's matching-funds program for gubernatorial candidates, which sets spending limits. He plans to use the millions he earned as cochairman of Goldman Sachs to finance his reelection campaign.

Contact staff writer Cynthia Burton at 856-779-3858 or cburton@phillynews.com.