Lowenstein then lauds Dimon’s exceptional risk-management skills:

That he manages to be the exception to the rule is a credit to his radar for trouble. Judy, his wife, whom he met at Harvard, claims he has an instinct for danger. Jay Fishman, who worked with Dimon in the ’90s (today he is chief executive of Travelers), says: “Jamie has a healthy regard for the idea that we will go through crises and that we will be lousy at predicting them. The flip side is he will run his businesses more carefully.” In the early ’90s, when banks were racking up huge losses in commercial real estate, Dimon ordered Fishman to study what would happen to Primerica if Citibank should fail. It was the sort of far-fetched risk that no other banker would worry about. A few years later, Primerica acquired Travelers, which had been weakened by Hurricane Andrew. Dimon demanded to see the catastrophe risk in every region the firm covered. Dimon did not have day-to-day control over insurance, but he routinely trespassed over organizational charts. He told Fishman to limit his exposure so that even a once-in-a-¬≠century storm would not cost the company more than a single quarter’s earnings. That was a highly unusual, and unusually conservative, approach.

THIS FALL, DIMON SPOKE at a conference sponsored by Barclays Capital: a thousand people crammed into the ballroom at a Manhattan Sheraton to hear him. The master of ceremonies began by noting that Dimon was also the lunchtime speaker at the conference in 2006, just before the mortgage bubble burst. It was interesting to recall, he said, who else spoke then: Kerry Killinger, the chief executive of Washington Mutual; Michael Perry, chairman of IndyMac; as well as executives from the subprime lender Countrywide Financial and Lehman Brothers. “Jamie told us that day about subprime exposure — his was the first major bank to talk about that,” the master of ceremonies said. “All of those other firms disappeared.”

What Lowenstein doesn’t do, at this point, is talk about how all this only serves to underscore how weak the U.S. banking system’s risk-management systems are: JP Morgan Chase survived in large part thanks only because it was lucky enough to have Dimon at its helm. If Stan O’Neal had been in charge, things would have turned out very differently indeed. As a result, it becomes not only sensible but necessary to hobble JP Morgan more than Dimon feels is warranted. You don’t set speed limits on the basis of how fast the very best drivers can safely travel.

Lowenstein shows just how uncritical he’s being in his section on credit cards:

Dimon laments that people — he means the Congress — don’t really understand the credit-card business. Last year, Congress enacted a law that restricted pricing flexibility — for instance, banks must give a 45-day notice before raising their rates, even when a borrower misses a payment. The legislation was meant to prevent sudden interest-rate increases that had caught cardholders unawares.

Dimon argues that all businesses charge for some things and not for others. For instance, restaurants give you the tablecloth and the silverware free and “mark up” the food. (Dimon loves to illustrate banking verities with examples from more familiar, and less threatening, industries.) Credit-card companies provide a service — convenience — “free,” but the business entails significant risks. In a typical month, Chase lends $140 billion to people, with no form of security. The bank earns interest on those loans, of course, but it has to pay expenses and eat the bills of cardholders who fail to pay them back. Before the bust, unpaid bills totaled roughly $6 billion; in 2009, when unemployment rose to double digits, credit-card losses soared to $18 billion, and the business plunged into the red. How to set rates that keep such a business both profitable and an attractive proposition for customers is what bankers do — or at least, what they try to do.

To compensate for its inability to quickly raise rates, Chase has decided to lessen its exposure by no longer offering cards to a portion of its customers that it deems the riskiest. This isn’t necessarily bad; if the mortgage mess taught us anything, it is that banks should exercise discipline.

Felix Salmon is an Audit contributor. He's also the finance blogger for Reuters; this post can also be found at Reuters.com.