In a truly courageous move, Brown-Vitter would require United States financial regulators to abandon Basel III. An earlier version of Basel did nothing to prevent the financial crisis and encouraged banks to binge on leverage.

Taxpayers would not be the only beneficiaries in the Brown-Vitter bill. Community banks, which weren’t responsible for bringing the nation’s economy to the brink, would be operating on a more level playing field with the jumbo banks. These large institutions have lower financing costs than community banks because the market understands that regulators will never let them fail.

“This bill will inject more market discipline on the financial services industry,” Mr. Brown said in an interview on Thursday. “The megabanks have a choice to make: they can increase their capital or bring down their size.”

Brown-Vitter has other attributes as well. It would bar bank regulators from giving nondepository institutions access to Federal Reserve lending programs. And it would make it harder for bank holding companies to move assets or liabilities from nonbanking affiliates, like derivatives bets held at a brokerage unit, to the protective umbrella of the parent company that might be rescued by taxpayers in a financial disaster.

Thomas M. Hoenig, the vice chairman of the Federal Deposit Insurance Corporation, supports the bill. “It’s finally taking the discussion in the right direction toward improving the stability of banks and the financial system more broadly,” Mr. Hoenig said in an interview on Friday. Brown-Vitter would also put the United States in a leadership position on financial soundness, he added, which other countries could emulate.

Both Mr. Brown and Mr. Vitter acknowledge, of course, that they will have to wage war with the financial services machine to move the bill forward. And last week, right on cue, the big-bank protection team went to work, warning of economic mayhem that would result if Brown-Vitter became law.

Standard & Poor’s, for example, published a report forecasting a possible credit crisis resulting from passage of the bill, “further reducing economic growth prospects.” With more money in a capital cushion, there would be less money to lend, the banks say.