But what Giuliani is promising to do as president is hold institutions to account—not help them make problems go away. On the campaign trail, Giuliani insists that all of his business dealings have been "totally legal, totally ethical," and that the media have already rooted out nearly every one of his clients. But without the cooperation of Giuliani Partners in answering these questions, there's no way to confirm his claims. "We comply fully with all F.E.C. rules and regulations," is all campaign spokeswoman Maria Comella would say on the subject.

Both publicly and privately, Giuliani Partners steadfastly denies it has anything to hide. A source who has a long history with the former mayor and knowledge of the company’s inner workings dismissed news accounts that Giuliani was being evasive. The source said most of Giuliani Partners’ client list had already been made known, and further insisted that the company's secrecy is a product of "the specific request of those clients."

Mitt Romney, one of Giuliani’s main rivals for the Republican nomination and a former consultant himself, might have no problem with that explanation. "Most clients want it to be confidential that a [consulting] firm is working with them," says Bob White, a longtime business partner of Romney's who is now the former Massachusetts governor's campaign chairman. But there’s a crucial difference in their career trajectories: Romney was out of the consulting business for more than 20 years when he announced his bid for the White House while Giuliani was building his consulting business and planning a presidential campaign at the same time.

Mike Wallace, a historian and co-author of the Pulitzer Prize-winning Gotham: A History of New York City to 1898, says Giuliani's closed-mouth approach would have grave ramifications in the White House.

"What troubles me is the possibility that a key element of his management style is a penchant for secrecy and keeping information out of the public’s eyes," Wallace says. "When he was in office he was extremely tightfisted about policing information that the public had every right to know. He had to be sued repeatedly by news organizations to get information."

Rival campaigns and the Democratic National Committee have begun a whispering campaign among political reporters in the hopes of pressuring Giuliani to disclose more of his mayoral documents and business records. A Freedom of Information Act request has already yielded the first potential bombshell of his campaign: Taxpayers helped fund his then-extramarital affair with Nathan. In addition, unfortunately for Giuliani, the private-sector work that has come to light has rarely been flattering. After Purdue Pharma, maker of the highly addictive painkiller OxyContin, ran into a host of legal and P.R. troubles in 2004, company officials were quick to trumpet their hiring of the former mayor, whom one heralded as "a sort of rock star."

But instead of being extricated from the OxyContin controversy, top executives were prosecuted for misleadingly claiming the drug was less addictive than other narcotics. In June, the lead prosecutor on that case told the New York Times that Giuliani was key in negotiating a plea deal that kept three Purdue executives out of prison.

Critics have pointed to the Purdue relationship as contradicting Giuliani’s claim that he is the true law-and-order candidate (as opposed to actor, lawyer, and former Senator Fred Thompson who has made similar claims). And Giuliani’s secretive and loyalty-driven management style—several key Giuliani Partners officers hail from his administration, and many have been reimbursed by Giuliani’s campaign for volunteer work—are raising questions about his judgment. That J word has been dogging Giuliani pretty hard thanks to his association with longtime associate Bernard Kerik, his former police commissioner. Partly on Giuliani’s recommendation, President George W. Bush nominated Kerik to be Homeland Security chief in 2004.

Giuliani severed his business relationship with Kerik after the nomination flamed out amid allegations that Kerik hired an illegal immigrant as a nanny, failed to pay all his taxes, and had two extramarital affairs. In November, Kerik was indicted on 16 federal corruption charges. Adding to Giuliani's potential woes is book editor and publisher Judith Regan’s $100 million lawsuit against News Corp. alleging that executives pressured her to lie about an affair she had had with Kerik after he was nominated to Bush’s cabinet. The reason, said Regan, the original would-be publisher of O.J. Simpson's book If I Did It, was to protect Giuliani’s political ambitions. News Corp. is a client of Giuliani Partners.