Kenneth L. Lay, the former chief of Enron, briefly addressed lawmakers today before he exercised his constitutional rights and refused to testify at a Senate Commerce Committee hearing.

"I come here today with a profound sadness," Mr. Lay told members of the Senate Commerce Committee. Then he declared, as expected, that he would exercise his constitutional right against self-incrimination.

"I am deeply troubled about asserting these rights," Mr. Lay said, saying he was concerned that people would conclude that he had "something to hide."

Mr. Lay said he had decided against testifying only after "agonizing consideration" and on the advice of his lawyer, Earl J. Silbert, who sat next to him.

"I respectfully ask you not to draw any negative inference," Mr. Lay said, whereupon he was excused and left the hearing room.

But as senator after senator made clear before Mr. Lay's brief remarks, they had already drawn negative inferences about the fall of Enron, Mr. Lay's role in the failure and the fact that Mr. Lay and other top Enron executives became rich while thousands of Enron employees lost their jobs and many ordinary investors saw their savings evaporate.

"You're the most accomplished confidence man since Charles Ponzi," said Senator Peter Fitzgerald, Republican of Illinois, referring to the swindler of yesteryear whose name has become virtually synonymous with pyramid schemes. Mr. Fitzgerald said he was tempted to call Mr. Lay a carnival barker, "except that wouldn't be fair to carnival barkers."

Mr. Lay sat stone-faced through most of the comments and as the glare of flashbulbs reflected off his face and forehead. But he shook his head slowly near the end of the statements as Senator Ernest F. Hollings, the South Carolina Democrat who heads the Commerce Committee, referred to him sarcastically as "Kenny Boy," the nickname that President Bush good-naturedly conferred upon Mr. Lay, his political benefactor and friend from Houston.

"Maybe we can get some good out of this situation," Mr. Hollings said, expressing the hope that an exhaustive inquiry into the Enron debacle might help relegate "cash and carry government" to the past.

Now in eclipse and disgrace, Mr. Lay was politically well-connected only months ago, and members of both parties benefited from his generosity. And while members of both parties talk off and on about regulating the spigots that pour money into political coffers, campaign-finance reform has always been a tough sell in the Capitol.

Mr. Lay appeared under subpoena before the Commerce Committee, one of several Senate and House panels looking into various aspects of Enron's collapse. Last week, two former and two current Enron officials declined to testify on Capitol Hill. And a former partner at Arthur Andersen, Enron's auditor, refused to testify last month.

After Mr. Lay left the hearing room, the panel heard William Powers, an Enron director who is the dean of the University of Texas Law School and led an internal Enron investigation, testify that documents shredded at Enron's Houston headquarters may have contained financial information that Congressional investigators were seeking.

"There may be information on those documents that were shredded that would have helped," Mr. Powers told the senators. He added that Mr. Lay bore "significant responsibility" for Enron's failure to prevent abuses in the partnership arrangements that may have masked the company's true financial condition.

But it was Mr. Lay whom the senators really wanted to hear.

"Mr. Lay has a story to tell," said Senator Byron L. Dorgan, a North Dakota Democrat who heads the Commerce Committee's consumer affairs subcommittee. How sad, Mr. Dorgan said, that Mr. Lay was declining to tell his story — a story about people at the top getting rich "while people at the bottom wound up losing everything."

Several senators suggested that the untold story was also a tale of corporate greed, of deliberately tangled partnership arrangements devised to inflate earnings and disguise losses and of shady off-shore entities created to avoid taxes.

Perhaps worst of all, some senators said, was that the Enron debacle might undermine the faith of the American people and people around the world in the capitalist system and the investments that fuel it.

"This is not capitalism," said Senator Gordon Smith, Republican of Oregon. "This is a conspiracy that may be a crime."

Senator John S. McCain, Republican of Arizona, recalled a speech that Mr. Lay himself made in 1999, a speech in which he stressed the importance of Enron's having directors who strived to do "what is right" and without "any hidden agendas."

What has happened at Enron in recent months "made a mockery of Mr. Lay's words," Mr. McCain said.

"The anger here is palpable," said Senator John Kerry, Democrat of Massachusetts. "Lives have been ruined, many lives."

Some senators invoked nautical metaphors to describe what happened to Enron, and their indignation over it.

"It was on his watch that the wreck occurred," Senator Conrad Burns, Republican of Montana, said of Mr. Lay.

Senator Ron Wyden, Democrat of Oregon, lamented that Mr. Lay's silence would make it harder for investigators to learn "why the Enron ship is at the bottom of the ocean."

Enron's leadership apparently violated "the most basic of moral principles," said Senator Jean Carnahan, Democrat of Missouri, saying that the company appeared to have been "without moral bearings" and like "a ship without a rudder."

In addition to the various Congressional panels, the Justice Department and the Securities and Exchange Commission are looking into the Enron affair.

Senator Olympia Snowe, Republican of Maine, said the company's collapse was a fall of "truly Homeric proportions." Speaking of Mr. Lay, she said, "His silence will not deter us from seeking the truth."