The national mood demands businessmen in handcuffs. And here's one already: Federal agents have arrested Bernie Madoff, the 70-year-old founder of a Wall Street brokerage, accusing him of bilking $50 billion from investors.

The Oedipal twist: Madoff's own sons, Andrew and Mark, turned Madoff in after he told them that the money-management arm of his firm, which ran hedge funds for wealthy investors, was "a giant Ponzi scheme." That term gets thrown around a lot, so we'll remind you of what it actually means: A scheme in which current investors are paid outsized returns not from investing profits but from money put in by new investors.

That is, according to an FBI agent's complaint, exactly what Madoff did:

deceived investors by operating a securities business in which he traded and lost investor money, and then paid certain investors purported returns on investment with the principal received from other, different investors, which resulted in losses of approximately billions of dollars.

All goes well in this kind of scheme until the money stops flowing in. Madoff told his sons that customers had sought to withdraw $7 billion, and he did not know if he could come up with the cash.

Madoff's lawyer, Dan Horwitz, touted his client's "unblemished record" to the Wall Street Journal. But rivals on Wall Street have questioned his curiously steady returns for years.

The complaints against Madoff are shocking. But mostly for the simplicity of the alleged swindle. A Ponzi scheme, in this day and age? It show the need for better hedge-fund regulation — boring! This was a rich-on-rich crime.

The case of Marc Dreier, a lawyer recently arrested on allegations of a $380 million hedge-fund fraud, is far more compelling, with faked-up websites and multiple cell phones. Prosecutors say he tried to sell fake debt instruments to a pension fund.

It all points to a much-needed sweep of the hedge-fund world. But neither Madoff nor Dreier seem to have played a significant role in the housing bubble that could end with 8 million homes in foreclosure. Yeah, the feds got their men. But we didn't get our scapegoats.