In one remarkable stretch from 1999 to 2001, he pushed laws and promoted policies that he says unshackled businesses from needless restraints but his critics charge significantly contributed to the financial crisis that has rattled the nation.

He led the effort to block measures curtailing deceptive or predatory lending, which was just beginning to result in a jump in home foreclosures that would undermine the financial markets. He advanced legislation that fractured oversight of Wall Street while knocking down Depression-era barriers that restricted the rise and reach of financial conglomerates.

And he pushed through a provision that ensured virtually no regulation of the complex financial instruments known as derivatives, including credit swaps, contracts that would encourage risky investment practices at Wall Street's most venerable institutions and spread the risks, like a virus, around the world.