A new round of regulation is clearly in order these days, and a Pecora-style investigation seems like a good way to jolt the Obama administration into action. After all, the financial revelations of today bear a striking resemblance to those of 1933. In his own account of his investigation, Pecora described bond issues that were almost certainly worthless, but which 1920s bankers sold to uncomprehending investors anyway. He told of the bonuses which the bankers thereby won for themselves. He also told of the lucrative gifts banks gave to lawmakers from both political parties. And then he told of the banking industry's indignation at being made to account for itself. It regarded the outraged public, in Pecora's shorthand, as a "howling mob."

The idea of a new Pecora investigation is catching on, particularly, but not exclusively, on the left.

It's probably not going to happen, though, in the comprehensive way that it should. The reason is that understanding our problems, this time around, would require our political leaders to examine themselves.

The crisis today is not solely one of bank misbehavior. This is also about the failure of the regulators -- the Wall Street policemen who dozed peacefully as the crime of the century went off beneath the window.

We have all heard the official explanation for this failure, that "the structure of our regulatory system is unnecessarily complex and fragmented," in the soothing words of Treasury Secretary Tim Geithner. But no proper Pecora would be satisfied with such piffle. The system was not only complex, it was compromised and corrupted and thoroughly rotten even in the spots where its mandate was simple.

After all, we have for decades been on a national crusade to slash red tape and stifle regulators. Over the years, federal agencies have been defunded, their workers have grown dispirited, their managers, drawn in many cases from antiregulatory organizations, have seemed to care far more about industry than the public.

Consider in this connection the 2003 photograph, rapidly becoming an icon of the Bush years, in which James Gilleran, then the director of the Office of Thrift Supervision (it regulates savings and loan associations) can be seen in the company of several jolly bank industry lobbyists, holding a chainsaw to a pile of rule books. The picture not only tells us more about our current fix than would a thousand pages about overlapping jurisdictions; it also reminds us why we may never solve the problem of regulatory failure. To do so, we would have to examine the apparent subversion of the regulatory system by the last administration. And that topic is supposedly off limits, since going there would open the door to endless partisan feuding.

But it's not only Republicans who would feel the sting of embarrassment. Launching Pecora II would automatically raise this question: Whatever happened to the reforms put in place after the first go-round?

Now a different picture comes to mind. It's Bill Clinton in November of 1999, surrounded by legislators of both parties, giving a shout-out to his brilliant Treasury Secretary Larry Summers, and signing the measure that overturned Glass-Steagall's separation of investment from commercial banking. Mr. Clinton is confident about what he is doing. He knows the lessons of history, he talks glibly about "the new information-age global economy" that was the idol of deep thinkers everywhere in those days. "[T]he Glass-Steagall law is no longer appropriate to the economy in which we live," he says. "It worked pretty well for the industrial economy, which was highly organized, much more centralized, and much more nationalized than the one in which we operate today. But the world is very different."

It turns out the world hadn't changed much after all. But the Democratic Party sure had. And while today's chastened Democrats might be ready to reregulate the banks, they are no more willing to scrutinize the bad ideas of the Clinton years than Republicans are the bad ideas of the Bush years.

"We may now need to be reminded what Wall Street was like before Uncle Sam stationed a policeman at its corner," Pecora wrote in 1939, "lest, in time to come, some attempt be made to abolish that post."