The government's extraordinary reaction to the financial crisis was both a medicine and a poison. Money saved the nation's largest banks, but also it institutionalized the idea that Wall Street firms could grow themselves to invincibility on a diet of bad bets, so long as the bets were big enough. If financial reform was supposed to cure the pernicious incentives of "Too Big to Fail" ... well, it failed. The nation's biggest banks are just getting bigger.

The top five U.S. commercial and investment banks -- Bank of America, J.P. Morgan Chase, Citigroup, Wells Fargo and Goldman Sachs -- have emerged from the financial crisis larger than ever. As of the third quarter of 2010, they had a total of $8.6 trillion in assets, according to data provider Capital IQ. That's 13.3% of all U.S. financial firms' assets, up from 11.8% three years earlier, when the financial crisis hit.

Size can be good, allowing banks to compete globally and provide services to customers at the lowest possible cost. But it also gives the top banks a lot of political influence. That could be a problem at a time when new financial-reform legislation has given U.S. regulators more leeway than ever in reshaping the rules by which the banks operate.

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