Since the day he announced his candidacy, New Jersey Republican gubernatorial candidate Christopher J. Christie has been pitching himself as the corruption-busting lawman who will return ethics to state government.

But lately, the former U.S. attorney has spent less time vowing to clean up Trenton than responding to allegations and defending his actions.

This week, after a report on NJN public television, Christie acknowledged that he had failed to properly disclose lending a subordinate in the U.S. Attorney's Office $46,000. He admitted not paying taxes on the interest he received, and said he would correct his tax returns and financial-disclosure filings.

Christie's replacement in the office, Ralph Marra, is under investigation, according to the Associated Press, to determine whether he made inappropriate public comments in support of Christie's campaign.

And this month, it was disclosed that Christie had spoken to Karl Rove, a top strategist under President George W. Bush, about a possible run for governor. Democrats immediately accused Christie of violating the Hatch Act, which bars federal employees, including U.S. attorneys, from engaging in political activities.

Democrats have been trying for months to tarnish Christie's record, criticizing him, for example, for awarding no-bid contracts worth millions of dollars to people including his onetime boss, former U.S. Attorney General John Ashcroft.

Until now, Christie has dismissed the attacks as partisan mudslinging and maintained a lead over incumbent Gov. Corzine in the polls.

But the most recent revelations, including Christie's first admission of a mistake, could well amount to the campaign's first serious challenge after months of relatively smooth sailing.

Corzine campaign strategist Tom Shea said serious questions remain about Christie's loan.

"This whole episode raises grave questions about impartiality in our justice system, and the public deserves answers," Shea said.

The Christie campaign did its best yesterday to sidestep the issue, making no comment on the loan and drawing attention to the state's latest unemployment statistics.

Christie's ethics platform, which he reintroduced on Aug. 5, includes more detailed disclosures for public officials.

Political analysts disagree about how much the recent events could hurt Christie with voters.

"This is really bad news for Chris Christie in the long run," said Patrick Murray, a political analyst at Monmouth University.

For someone "who is basing his entire strategy on portraying himself as someone who is different than a typical politician, this can be a fatal blow to his campaign," Murray said. "He's basically put all his eggs in his ethics basket.

"It's not so much that he's unethical, but that he's no better than any other politician. That's a really easy story for Corzine to tell."

More than any other candidate in the race, Corzine, a multimillionaire former Goldman Sachs chief executive officer, has the means to tell his story to the public. His advertisements attacking Christie on ethics before this week had already helped drive up Christie's unfavorable ratings.

Murray said that for Christie to recover, he would need to change gears very quickly and come up with a new message, perhaps on property taxes, which Murray said is really the only issue on voters' minds. According to at least one recent poll, voters trust Christie more than Corzine to tackle property–tax reform.

Joseph Marbach, a political analyst at Seton Hall University, thinks Christie has enough time before the election to recover.

In August, he said, most voters are not tuned into politics. "If Christie can adequately explain these charges and if the press is satisfied with the explanation, these issues will by and large go away and new issues will develop as we move into October and November," Marbach said.

Marbach doesn't see Christie's loan to fellow prosecutor Michele Brown as a deal-breaker for most voters. He compared the loan to Corzine's loan-turned-gift to former companion Carla Katz, who at one time headed the largest state workers union.

"The public doesn't seem to get terribly concerned over how individuals dispose of their own resources or their own wealth," Marbach said.

Ingrid Reed, New Jersey project director at the Rutgers University Eagleton Institute of Politics, said she worries that people who saw Christie as a way out of New Jersey's ethical murkiness would become even more skeptical and cynical about anyone seeking elected office.

In the last two gubernatorial elections, voter turnout was below 50 percent, Reed said.

"It's almost like people are thinking it doesn't make any difference who's governing New Jersey," she said.

One possible beneficiary of the last two weeks could be Chris Daggett, an independent candidate trying to appeal to voters fed up with both political parties.

Daggett, who is scheduled to present his ethics platform today, said Christie's situation highlighted the problem of being a single-issue candidate.

If a single-issue candidate is found to have flaws on that issue, he said, "it starts to question the legitimacy of his ability to carry the day in the Legislature on some of the things he wants to get done.

"I think New Jerseyans are more and more prepared to hear the truth instead of what people will say to get elected."