"Failure does not equate to a crime,” said Kenneth Lay, the chief executive of Enron, as he proclaimed his innocence in the 2001 collapse of the company.

With investors and the economy reeling from the financial crisis, there is much public clamoring for an Enron-like crackdown, complete with executives in handcuffs being paraded before the cameras.  (A federal jury convicted Lay of fraud and conspiracy charges, but he died before he was sentenced.)

Most legal experts, however, predict that it will be tough to establish that crimes were committed.  Failure, in form of the financial tsunami that rocked nearly every bank and institution around the world, will be an effective defense this time around.  Hundreds of billions of dollars have been lost, banks and Wall Street firms have disappeared, stocks of financial companies have tumbled. “Why would everybody have the same fraudulent thought?” notes Robert Giuffra, a securities litigator at Sullivan & Cromwell.

Still, that won’t stop prosecutors, says Robert Plotkin, a lawyer with the Washington office of McGuire Woods and who worked for the defense in the Enron investigation. “A lot of this is going to be politically motivated,” he says. “Almost as a condition for any kind of loans or bailouts, there already has been a ratcheting up of investigations.”

The prime target for the prosecutorial cross hairs is the collapse of Lehman Brothers, the Wall Street firm that filed for bankruptcy protection on September 15. Its demise is at the center of at least three criminal investigations – by federal prosecutors in Manhattan, Brooklyn, and in New Jersey.

In an unusual move,  Manhattan federal prosecutors announced in October that they were cooperating with investigators from the office of the New York attorney general, Andrew Cuomo, to investigate the trading in credit-default swaps that contributed to Lehman’s meltdown. With $600 billion in assets, the Lehman bankruptcy was the largest in U.S. history.

“There is a decent chance that Lehman will be the poster child” of these prosecutions, says Peter Henning, a professor of criminal law at Wayne State University and the founding editor of the White Collar Crime Professors blog. “When that much money gets lost, someone has to get the blame, and so it would not surprise me if there was a prosecution of Lehman management for misleading investors.”

But Henning expects a case very different than those that focused on the complex accounting schemes that caused the collapse of Enron and WorldCom. “In the dying gasp at Lehman, they painted too pretty a picture: It will be a disclosure case as opposed to accounting fraud.”

A good comparison, says Henning, is the pending criminal prosecution of David Stockman, the former Reagan administration official and former chief executive of Collins & Aikman, the auto parts supplier, who is headed to a trial early next year on fraud charges. The indictment against him portrays a chief executive engaged in a web of lies and fraud about the financial forecasts of his company to gain access to credit, which filed for bankruptcy in May 2005.

Such cases are built by sifting through the trail of emails and internal communications and contrasting them with what is said to the public. “Part of the Enron case was the same thing,” Henning says. “What did they know and what were they telling to the public. That is the great thing about white-collar cases. It is never a factual dispute, it is ‘what did you know and when did you know it and what did you say?’”

The financial crisis has created another hurdle for prosecutors: A lack of resources. When the Enron task force was put together, no expense was spared.

“There aren’t going to be these grand enterprises to allow the prosecutors to put together more nuanced, complex malfeasance cases,” says John Hueston, one of the lead prosecutors of the Enron Task Force and now a partner at Irell & Manella of Newport Beach, California. “What they are left with is trying to make quick-hit cases --- narrowly burrowing into emails to see if there is chatter contrary to public disclosures.”

The only prosecution to date,  the June indictment of two  former Bear Stearns hedge fund managers, zeros in on emails and internal conversations. Critics of that case say that  those communications, boiled down to a debate about the  state of the subprime mortgage market between the two executives who oversaw the funds. The indictment against the two managers, Ralph Cioffi and Matthew Tannin, was unsealed the same day that the F.B.I. announced it was launching a crackdown against abuses in the mortgage business, called  “Operation Malicious Mortgage.” The F.B.I.’s press release cites charges against 406 people, but mentions only the Bear Stearns executives by name.