Teflon Bob Rubin may have to buff up his non-stick coating as he braces for a fresh barrage of criticism over his failure to help Citigroup navigate the credit crunch.

As Vikram Pandit, Citi’s CEO, plows on with his boardroom shake-up, many investors and analysts are surprised that Rubin, former Treasury Secretary in the Clinton administration and all-around Wall Street untouchable, has managed to hang on to his co-chairmanship of the bank’s executive committee.

“It is extraordinary how he is treated with kid gloves,” said Peter Wallison, former general counsel to the Treasury Department and chair of financial policy studies at the American Enterprise Institute, a Washington think tank.

“They call him Teflon Bob for a reason,” said one leading analyst, speaking, like many others, only on the condition of anonymity.

“I am reluctant to pin all of Citi’s troubles on the back of one man,” said another veteran Wall Street banking analyst, adding, “but you have to ask, why is he there if not to advise.”

The criticism is fueled by frustration that Rubin and the rest of Citi’s board failed to sound the alarm as the bank piled up risks before the credit crunch, saddling the company’s balance sheet with more than $20 billion in losses in less than a year.

Rubin has been singled out by the critics for his failure to act or even to speak up about the massive risks being accrued by Citi’s fixed-income division, given his background, which is steeped in financial regulation and Wall Street lore.

Rubin has been in the middle of a number of episodes that helped create the intertwined credit crunch strangling Wall Street today.

His crowning achieve-ment at Treasury was the repeal of the Glass-Steagall Act, the Depression-era banking law that kept heavily regulated and insured banks from investing in sketchy products like less regulated brokerages do.

Today, less than nine years later, banks like Citi are writing down tens of billions of dollars in risky subprime-mortgage securities that are helping to strangle the economy.

Without Rubin’s efforts to repeal the Act, which came after more than 20 years and $300 million of lobbying on Wall Street’s part, the huge Citibank-Travelers merger that created Citigroup 10 years ago this week would likely have foundered.

Then there was the Enron collapse when Rubin, acting in his capacity at Citi, called old chums at Treasury in an effort to get the government to intervene with the ratings agencies about to downgrade the energy group’s bonds.

“That kind of action should produce an independent counsel investigation,” said Wallison, “But not for Rubin.” When faced with such criticisms, Rubin tells confidants that he has long warned in speeches and in interviews of the dangers of too much risk.

If that’s the case, why didn’t he tell anyone at Citi? People familiar with Rubin’s thinking claim the Wall Street veteran doesn’t think it’s his job to warn Citigroup of risk. As chairman of the board’s executive committee, Rubin’s job, he has told people, is to get good people on the board and not advise executives.

But after being the second-highest paid person at Citi – and earning more than $18 million in 2006 – some critics are asking what exactly he does for that kind of money. He has also accumulated $84 million in deferred compensation.

In his defense, a Citi spokeswoman said: “Bob Rubin serves in important strategic advisory and representational roles for Citi. He does not have operating responsibility and was not involved in managing trading activities or in the independent risk monitoring activities.”