Only three months after the enactment in July of the Dodd-Frank Act, the financial regulation legislation that was intended as a response to the financial crisis, a section of the act has already been repealed. Though that effort — a bipartisan rollback of the ability of the Securities and Exchange Commission to exempt some data from the Freedom of Information Act — shows that Congress is not averse to rethinking parts of the law, it is small potatoes compared with the changes that some opponents of Dodd-Frank would like to see. Those include reining in the powers of the Consumer Financial Protection Bureau, reconsidering limits on debit card fees and restricting the budgets and growth of the S.E.C. and the Commodity Futures Trading Commission. In addition, Republicans and opponents of the law would like to reverse what they call the institutionalization of “too big to fail” for the largest financial companies.