Those who say nothing useful came from last week's hearings of the Financial Crisis Inquiry Commission exaggerate—by, say, one or two percent.

From Citigroup's Chuck Prince we learned that the bank felt it must continue to participate in some markets even when it thought pricing had become crazy, because otherwise it would lose the employees who specialized in that business.

From Robert Rubin, we learned (again) that the Clinton administration was a paragon of fiscal responsibility, a pearl he vouchsafed though it had not the slenderest connection to the subject at hand.

Former Citigroup executives Charles Prince (left) and Robert Rubin. Associated Press

From Bill Thomas, the commission's vice chairman and a former GOP congressman, we learned the inquirers are getting insufficient time to master their brief—easy to believe given their reliance on the adjective "toxic" to substitute for any curiosity about the securities at the heart of the meltdown.

Collateralized Debt Obligations, or CDOs, are not so hard to fathom. A company is formed to collect, for instance, the payment streams of mortgage bonds and pay them out to investors who buy new securities of different grades—the best, or "super senior," get every dime coming to them before holders of the lower grades get anything.

Citi held or committed itself to hold some $40 billion of these on its balance sheet of more than $2 trillion—commitments that senior management didn't even know existed until late in the game, because their underlings saw them as near-riskless, not least because they were backed by bond insurance.

What exactly was it about these securities that caused a global panic—that caused, in the words of Goldman Sachs, a situation in which "institutions were hoarding cash and were unwilling to transact with each other"?

Was it fear that banks wouldn't be able to sell these now-illiquid securities to meet their own obligations?

Was it fear that government would force banks to recognize accounting losses on them so great that the banks would be rendered insolvent?

The question is crucial because panic was the key actor in the drama—turning a severe housing correction in a handful of U.S. states into a global calamity.

The most interesting panel of witnesses consisted of several Citi executives who ran this business. A question the inquisitors failed to ask is how these supposedly super-safe securities are performing today. Have they been able to withstand the surge in mortgage defaults? Do they continue to pay? The question begged to be asked, but Mr. Thomas was too busy assuring the Citi executives that the commission's final report "won't contain one word of what you folks just told us" and then promptly berating them over whether they lost "one night of sleep over what happened."

Where curiosity might have been useful, the commissioners preferred to shower disdain on the Citi executives for failing to forecast a complex disaster practically no one forecasted—unprecedented downgrades to the CDOs by the rating agencies that previously had blessed them, as well as downgrades to the bond insurers, which together forced Citi to recognize huge accounting losses on its CDO holdings.

The closest we got to the important follow-up question came when Mr. Prince, unbidden, blurted out: "It's entirely possible that at some point in the future people will make a lot of money from these instruments because they will pay out. But, again, the debate now isn't about those kinds of issues. The debate is about, 'We have to have market-to-market accounting as a theoretical purity.'"

We do know how the crisis ended. Government removed the fear that banks wouldn't be able to meet their own obligations by providing them with liquidity. Government also removed the fear of what government itself might do, by refraining from using its regulatory authority to declare banks insolvent on a mark-to-market basis.

One functional description of the crisis, then—at least from the perspective of who got rich when, which seems to be Mr. Thomas's main concern—is a giant hiccup in the value of certain bank-held assets. That hiccup allowed certain nervy hedge funds to make a killing as the assets crashed and others to make a killing as they now rebound.

Why was this opportunity created? How did the banks' own misjudgments contribute to this shifting of vast wealth from their balance sheets to those of speculators? How did government uncertainty and hesitancy in handling the crisis facilitate this transfer? How can Washington backstop the financial system (as it apparently must) without fostering the kind of incentives that eventually require the safety net to be invoked?

Let's be realistic here—in the time available to the panel, given its make-up, and given Mr. Thomas's descent into popinjayism, there's little chance that somebody with an interesting mind will take control and issue a report that's anything more than a distillation of well-worn motifs already in the media, adding nothing illuminating to the history of this episode.