The remarkable spending by Mr. Skilling is paying for a phalanx of lawyers, document crunchers and other specialists that would be far out of reach for the average criminal defendant. Those on the payroll have included an economist and a public-opinion pollster. The team has sifted through millions of pages of records and sat through hundreds of hours of depositions and hearings in other Enron cases, looking to glean any nugget that could work to their advantage.

Kathryn Ruemmler, deputy director of the Justice Department's Enron Task Force, declined to comment on the defense's spending or other aspects of the case.

Mr. Petrocelli, a partner at Los Angeles-based O'Melveny & Myers LLP, argues that the scope of Enron's operations and the breadth of the criminal charges against Mr. Skilling require an unprecedented defense effort. Enron, whose peak revenue reached $100 billion a year, collapsed into bankruptcy in December 2001. Mr. Skilling was indicted in February 2004, and the charges include insider trading.

Mr. Petrocelli says corporations have a lot at stake in Mr. Skilling's defense. The lawyer seeks to prove that the alleged crimes were actually commonplace and legitimate business practices, used for such routine purposes as managing cash flow and hedging against losses on investments. "This is probably the most important case in business history," says Mr. Petrocelli.

Adds Mr. Skilling: "I believe strongly that this is a business case. I don't believe that I'm involved in a criminal case."

While some 30 other people have been criminally charged in connection with Enron, Messrs. Lay and Skilling have long been the prime targets. The two men were the public faces of Enron, the only people to hold the chief executive's post and, according to the government, the two leaders of an elaborate scheme to hide the company's mounting financial problems from the public. Though officially No. 2 at the company for much of the period in dispute, Mr. Skilling was widely viewed as the man most responsible for building and running the Enron colossus.

Both defendants chose lawyers who mirrored their own personalities. Mr. Lay's lawyer, Mr. Ramsey, is a veteran Houston criminal attorney with a folksy demeanor that masks a shrewd and tough mind, say people who know him. In 2003, he helped win the acquittal of Robert Durst, scion of a wealthy New York real-estate family, on a charge of murdering and dismembering a man. Mr. Durst claimed self-defense.

Mr. Petrocelli, like his client, is smart, intense, and willing to argue over even small points. "I value passion probably more than any other attribute," says Mr. Skilling, adding that he was impressed by Mr. Petrocelli's experience in business cases. Mr. Skilling's team also includes two lawyers, Ron Woods and Mark Holscher, with criminal-law experience and another business litigator, Randy Oppenheimer.

Around the time of Enron's collapse, Mr. Skilling hired O'Melveny & Myers to help him with the wave of government investigations and shareholder lawsuits that were springing up. Mr. Petrocelli says he had nothing to do with the case -- and paid little attention to the Enron scandal -- until just before Mr. Skilling's indictment, when colleagues brought him into the matter. He says that at his first meeting with Mr. Skilling he noted he wasn't a criminal lawyer. The client replied: "Great, I'm not a criminal."

Mr. Petrocelli has pushed himself into unfamiliar territory before. Working as an auditor at a bank in Los Angeles after college -- a job he didn't like much -- he enrolled in a night law school and graduated first in his class. After joining a small Los Angeles law firm as a litigator, his profile skyrocketed in 1995 when he got involved in a suit related to the O.J. Simpson case.

Mr. Simpson had just been acquitted in the murders of his ex-wife and her friend, Ron Goldman. A business client of Mr. Petrocelli's helped introduce him to Fred Goldman, Ron's father, who was looking to sue Mr. Simpson. Fred Goldman recalls being impressed by Mr. Petrocelli's record as a litigator and his candor. "He was very upfront and honest," says Mr. Goldman. "He said that he had never done a suit like this before."

In Mr. Goldman's civil suit for wrongful death, where the burden of proof was lower than in a criminal trial, the jury awarded a $33.5 million judgment against Mr. Simpson. Mr. Petrocelli garnered a bonanza of press attention, a $2 million advance for a book called "Triumph of Justice" and eventually an offer to become a partner at O'Melveny, one of the biggest law firms in Los Angeles.

In his Simpson book, Mr. Petrocelli says his motto for the case was "less is more." Unlike the Simpson criminal trial, which meandered on for months, Mr. Petrocelli wanted to keep his case against the former football star relatively short, simple and tightly focused on the two murders.

Same Motto

Today, the Enron prosecutors have essentially the same motto against Mr. Petrocelli's current client. Prosecutors long worried that the financial details of the case could leave jurors bored, befuddled and unwilling to convict anyone. But the government hopes a recent guilty plea by Messrs. Skilling and Lay's co-defendant, former Chief Accounting Officer Richard Causey, will simplify the case and reduce the need to get into accounting arcana.

The government wants to persuade jurors that the case is simply about two rich and powerful men lying to protect their troubled business empire. Mr. Petrocelli's task is to show that it wasn't so simple. The matters at the heart of the government's indictment involve sophisticated accounting and financial decisions that were fully vetted by Enron's outside lawyers and auditors, says Mr. Petrocelli.

Case in point: Enron's decision in early 2001 to move part of its highly touted retail-electricity business under the umbrella of its much larger wholesale-energy operation. The indictment alleges that the move was designed to hide hundreds of millions of dollars in losses at the retail unit. Not so, says Mr. Petrocelli. He calls the move an ordinary reorganization to eliminate duplication and improve efficiency. He also disputes that there were losses to be hidden. Plus, he says, Enron's outside auditors approved the shuffle.

The lawyer has lined up more than a half-dozen expert witnesses covering the major aspects of the case. The indictment contends that Mr. Skilling grossed nearly $63 million from Enron stock sales in 2000 and 2001 while holding "material, nonpublic information" about the company's troubles. An expert stands ready to dispute that and to compare Mr. Skilling's trading to senior executives at other big companies, says a court filing.

Another expert is ready to dig into the special-purpose entities -- off-balance-sheet vehicles that the government says Enron used to hide losses. The defense is expected to argue that Enron's use of the entities met all necessary accounting and legal criteria.

Still another expert has been enlisted to go head-to-head with the government over Enron's dealings with outside partnerships run by its former chief financial officer, Andrew Fastow, who has pleaded guilty and is expected to be a major government witness. The government contends that Mr. Skilling and others used the Fastow partnerships to manipulate Enron's results.

Prosecutors have objected to the defense's planned expert barrage on various grounds, including the argument that much of their testimony would be irrelevant to the specific charges. Judge Lake has yet to rule on the dispute.

Pretrial Skirmishing

Mr. Petrocelli has already called on experts in the pretrial skirmishing. He requested that Judge Lake move the trial from Houston, Enron's hometown, because of the negative feelings and news coverage here. A boxful of documents filed in support of the motion included a public-opinion poll, taken in Houston and three other cities, and an analysis of local news coverage in those cities purporting to show that Messrs. Skilling and Lay couldn't get a fair trial in Houston.

A professor of sociology, Rice University's Stephen L. Klineberg, submitted a paper supporting the motion. Prof. Klineberg, who specializes in the study of community attitudes, spoke of the "symbolic importance" of Enron's rise and fall to Houston's collective psyche. Meanwhile, an economist wrote that Houston jurors might want to convict Messrs. Skilling and Lay so as to seize their wealth for former Enron employees and shareholders.

Mr. Lay's defense team also asked to move the trial -- in a two-page document that expressed support for Mr. Skilling's voluminous filing. Judge Lake turned them both down. The defense for both men recently renewed the request with the judge following Mr. Causey's guilty plea.

Mr. Petrocelli concedes that the judge has turned down most of his side's major pretrial motions. "I am very disappointed in our lack of progress," he says, while calling the filings necessary. Even the rejected motions, observers say, serve some purpose. They could help Mr. Skilling in an appeal if he is convicted, and they keep the government busy responding.

As the trial nears, Mr. Petrocelli, a New Jersey native, is adding some local touches. He now sports a pair of cowboy boots and makes an occasional stab at a Texas twang. During a recent breakfast meeting, while showing off his boots, he pointed a pugnacious finger and proclaimed, "I'm now a full-fledged Houstonian and I'm not leavin' town until Jeff Skilling is a free man."

Write to John R. Emshwiller at john.emshwiller@wsj.com¹