Sandy Weill, former chairman of Citigroup, exits Carnegie Hall in...

Sandy Weill, former chairman of Citigroup, exits Carnegie Hall in New York where the annual shareholders meeting was held. Credit: AP, 2008

After a global financial crisis, a massive bailout by taxpayers and an outrageous global rate-rigging scandal, we now hear from the man most responsible for the shape of modern banking that his vision for it was a mistake.

More or less, anyway. What actually happened was that retired Citigroup chief Sanford Weill said in a CNBC interview that America's troublesome banking giants should be broken up and perhaps restored to being really big regional banks -- the way they used to be.

Weill also wants us to go back to the days when banks were barred from risky investing, and investment firms were barred from regular banking.

Given all that's happened, these ideas aren't very controversial, except perhaps to bankers. But they are shocking indeed coming from Weill, who did more than anyone to create the modern American financial colossus with its brittle feet of clay. Weill built Citigroup, parent of Citibank, into what was for a while the world's largest financial institution. Weill also was instrumental in overturning Glass-Steagall, the Depression-era law that kept commercial and investment banking safely separated.

Weill deserves props -- if really small ones -- not just for admitting he was wrong, but for implicitly repudiating the crowning achievement of his life's work. Yet he also deserves brickbats for having worked so hard to make our recent financial disasters possible.

Fortunately, we're already on our way down the road he now sees as the right one. Two years ago, despite bank opposition, Congress enacted a latter-day version of Glass-Steagall called the Volcker rule, named for former Federal Reserve Chairman Paul Volcker. It will bar banks from trading with their own money and certain other risky activities. The rule has yet to take effect because regulators have struggled to draw workable distinctions between some bank activities that will be allowed and others that won't.

In retrospect, it would have been better to do what Weill advocates: Break up the behemoths by shearing off their investing arms. If such a plan ever becomes law, we can call it the Weill rule, and it will make a better testament to the man than the sprawling banking company he seems to regret assembling.