The arguments for Messrs. Lay and Skilling, the only two people who ever headed Enron before its bankruptcy, capped more than three months of testimony in the landmark trial, whose outcome will be a measuring stick in the government's crusade against corporate crime.

The government's indictment is a "fictional world" of alleged crimes that prosecutors are using to try to have Mr. Lay "locked in a cage for the rest of his life," said Bruce Collins, one of the attorneys for Mr. Lay, Enron's former chairman.

"The facts show the innocence of both these men," said Daniel Petrocelli⁵, the lead attorney for Mr. Skilling, Enron's former president. "Just because it's Enron doesn't mean we have to lose our common sense."

The government maintains the giant energy trader faced mounting financial problems in the two years before bankruptcy and took various illegal steps to hide them. On Monday, prosecutor Kathryn Ruemmler ridiculed the defense contention that no major crimes were committed at Enron, running through a litany of alleged business and financial problems at the company.

To deny such problems "is just absurd," she said. Saying jurors should focus on the former Enron executives who testified that they had "committed frauds" with the defendants, she urged the jury to convict Mr. Skilling, 52 years old, on all 28 counts against him and Mr. Lay, 64, on the six counts facing him.

The defense maintains that Enron was a healthy company felled by a market panic that was sparked partly by a series of Wall Street Journal stories raising questions about the company's financial dealings with partnerships run by Mr. Fastow. The Journal has said it stands by its reporting on Enron's activities.

The defense's closing arguments provided an opportunity to summarize the testimony of more than four dozen witnesses -- including both defendants -- thousands of pages of documents and hours of videotaped public presentations by Messrs. Skilling and Lay to investors and others. But attorneys also argued that jurors should focus on the fate of two men and not negative news coverage of the Enron scandal, which set off a wave of corporate and governmental reforms -- and helped bring down Enron's outside accountant, Arthur Andersen.

In reaching a verdict, the jury will, in some ways, bring a close to the era of corporate scandals. Enron's fall sparked a raft of investigations, including a criminal probe by a special federal task force. To date, some 30 people have been criminally charged in the Enron case, and more than a dozen have reached plea agreements with the government. Several of those testified against Messrs. Lay and Skilling in hopes of getting leniency when sentenced.

Though Ms. Ruemmler handled the entire first day of the government's closing argument, five different attorneys spoke yesterday, four of them for Mr. Lay. The number of lawyers for Mr. Lay reflected the fact that his lead lawyer, Michael Ramsey, missed a large part of the trial because of health problems. He recently returned and was one of the four attorneys who spoke.

Partly due to the absence of Mr. Ramsey, a colorful and respected veteran of the Houston criminal-defense bar, Mr. Petrocelli has been the dominant defense attorney in the trial and remained so yesterday. In a presentation lasting more than three hours, he paced the courtroom in front of the jury, his voice ranging from a near-shout to a bare whisper, as he worked to ridicule the government's case and humanize his client.

Mr. Petrocelli started off by admitting, as his client had when he took the stand several weeks ago, to being "a little nervous this morning." The reason, he added, was because "for the last two years I've felt like I've had Jeff's life in my hands." Once his closing argument was finished, he told the jury, "I then turn him over to you." Later, he gestured toward his client and asked jurors to "look him in the eyes… See if you see a criminal."

Defense attorneys also asked jurors to focus on the government's witnesses and their plea agreements. In the effort to win leniency, these witnesses "had been robbed of their free will" and said "false things about Jeff and Ken" in order to satisfy prosecutors, said Mr. Petrocelli. Said George Secrest, another attorney for Mr. Lay: "These witnesses were not unvarnished. They were shellacked."

The attorneys for both defendants also reminded jurors that the government didn't call a number of potentially key witnesses. Most prominent among these was former Enron Chief Accounting Officer Richard Causey, whose name came up frequently in connection with involvement in alleged wrongdoing. According to the government "Mr. Causey was up to his eyeballs in this fraud," said Mr. Petrocelli. "Where is he?"

Mr. Causey had been a co-defendant in the case until he pleaded guilty last December to one count of securities fraud -- leading to widespread speculation that he would be a key government witness. At the same time, defense attorneys talked of possibly calling him in the belief that he would say some things helpful to their cause. In the end, neither side thought it worth the risk of bringing Mr. Causey to the stand, out of concern that he would say things harmful to each side's position even as he said other things that would have been helpful.

Throughout the day, the defense often mocked and tried to belittle the government's case. Mr. Petrocelli characterized it as a "hodgepodge" of issues, supported by "snippets" of evidence in an effort to criminalize what were actually common and legal business practices. If the government's argument is believed, "We might as well put every CEO in jail," he said.

Write to John R. Emshwiller at john.emshwiller@wsj.com⁶ and Gary McWilliams at gary.mcwilliams@wsj.com⁷