Saturday was a strange and significant day in the annals of the Bernard Madoff affair. On that day—the two-year anniversary of his arrest as the biggest con man in history—his eldest son, Mark, committed suicide by hanging himself with his dog’s leash. That day was also the deadline for the filing of lawsuits against the people and entities believed to have profited from Madoff’s monumental fraud.

For members of the public watching from afar, the legal maneuverings may seem like a kind of delayed retribution—partial compensation, perhaps, for the general dearth of activity by prosecutors. But is it?

For Irving Picard, the court-appointed trustee, what's afoot is not vengeance, but rather the grim, remorseless role of a collection agency. He is tasked with retrieving as much of the $65 billion Madoff loot as he can. Picard has sued banks, personal associates, friends, and family members—including Mark Madoff, who wasn’t charged with any criminal activity, but who was said to be despondent over all that had happened in the last two years.

It certainly is true that Picard has an ace legal team, which includes John Moscow, a highly regarded former white-collar prosecutor with the office of former Manhattan District Attorney Robert Morgenthau. Tom Ajamie, a securities lawyer in Houston who represents investors, tells me that Picard’s team “is extremely experienced and skilled at recovering money from banks and others who are involved in complex international financial frauds.” I remember well how Moscow’s team pursued penny-stock crooks in the 1990s, such as its prosecution of the A.R. Baron stock-fraud case.

But it’s possible that Picard may have bitten off more than he can chew. If so, this last gasp of legal activity seems more like a death rattle than a thunderclap.

The reason lies in the nature of the cases that he has brought against banks like JPMorgan Chase, UBS, and HSBC and the fundamental question: Were the banks negligent in their dealings with Madoff? Should they have blown the whistle on him? How extensive was their obligation to the public?

One lawsuit filed shortly before the deadline accuses seven major banks, including Citigroup and Bank of America, of functioning as a “spigot of money” for Madoff. Picard contends that the banks “received transfers of money from Bernard L. Madoff Investment Securities through numerous Madoff feeder funds at times when they either knew or should have known of Madoff’s fraud.” The banks have vigorously denied wrongdoing, saying that they had no idea Madoff was operating a Ponzi scheme.

Bill Singer, a former NASD securities lawyer now in private practice, told me that he is no fan of the big banks, but believes that Picard’s approach is an exercise in twenty-twenty hindsight that lacks a proper legal foundation. For one thing, he says, if the banks are culpable, what about the regulators? Why aren’t they being sued? The bank suits, he says, “stink of rank hypocrisy.”

The last-minute suits being pursued by Picard are known in the legal community as “clawback” lawsuits, as they are designed to extract money from people who benefited from Madoff, for redistribution to his victims. Among Picard’s targets: Austrian banker Sonja Kohn, who Picard believes should pay $19.6 billion to compensate for her longtime partnership with Madoff.

Picard has already reached settlements with a number of investors in Madoff’s funds who received illusory “profits” that turned out to be money stolen from other investors. Among them was Boston philanthropist Carl Shapiro, who recently agreed to pay back $625 million that he received from Madoff. To date, Picard has filed suits seeking $50 billion and has recovered about $2.5 billion.

Members of Madoff’s family have been hit with similar lawsuits, based on the same legal theory—that they have to cough up ill-gotten gains.

Singer says that he has no problem with the suits against Madoff family members, which he says are amply justified under existing law as possible “third-party relief defendants,” who benefited from Madoff without necessarily being culpable. But the suits against the banks are based on assumptions that, he says, are far more tenuous. Picard, he says, “is not delineating between having a feeling and knowing something to a legal certainty.”

In the suit against JPMorgan, a lawyer for the trustee contended in a statement that "JPMorgan was willfully blind to the fraud, even after learning about numerous red flags surrounding Madoff." JPMorgan officials responded by saying that Picard’s contentions are "irresponsible and over-reaching."

Singer feels about the same way. Even if the banks suspected that Madoff was a crook, Singer says, there was no legal obligation for them to “walk out in the middle of Times Square and blow the whistle.” Harboring suspicions, or hearing rumors, is not “knowledge of a fact.” And if the banks had indeed gone to the U.S. attorney’s office or Securities and Exchange Commission, he says, the response might have been that “you should have come to us a month earlier.”

And what about the regulators? For years, whistle-blower Harry Markopolos sought without success to get the SEC interested in his contention that Madoff was a crook. “If the implication is that it was widely known in the financial community that Madoff was crooked, the same can be said for regulators,” Singer says, though he concedes that the barriers to suing regulators, such as the legal doctrine of sovereign immunity, are high.

Of course, prosecutors have been known to pursue novel legal theories in the past, and these cases may be aimed at extracting settlements from the banks. Whether or not Picard’s suits succeed, even in extracting settlements, it won’t really matter from the standpoint of the financial markets. Madoff’s implosion, coming at the height of the financial crisis, damaged investor confidence in the markets—perhaps permanently. No lawsuits, settlements, or legal saber-rattling is going to undo that particular damage.