Senate Banking Committee Chairman Tim Johnson (D-S.D.) said in a hearing Tuesday he would counter any effort to repeal sections of the Dodd-Frank Act. The committee heard testimony from Financial Crisis Inquiry Commission Chairman Phil Angelides, as it reviews the report and determines if the Dodd-Frank Act sufficiently addresses the regulatory gaps that led up to the financial crisis. Republicans in the House say the reform goes too far and rolled out several repeals in March, and later three more to dilute the powers of the newly created Consumer Financial Protection Bureau. Earlier in the year, Rep. Michele Bachmann (R-Minn.) attempted to repeal the entire bill. But Johnson said such actions are "dangerous and irresponsible." He said some of the repeals proposed would take the financial system back to the same weaknesses that exposed investors and taxpayers to uncertain risk. "We cannot allow Dodd-Frank to be dismantled," Johnson said. "As costly as the Great Recession has been, we simply cannot afford to go back to the old financial system that destroyed millions of jobs and cost the economy trillions of dollars. Congress enacted the Dodd-Frank Wall Street Reform and Consumer Protection Act to address these problems, and it must be fully and carefully implemented." Angelides backed Johnson and so did, to an extent, Sen. Richard Shelby (R-Ala.), who recently led a GOP letter to President Obama pledging not vote for any CFPB director until Republican reforms of the agency were signed. "There were gaps," Angelides said. "The SEC could have reduced risk and increased capital and liquidity at investment banks. They did not do it. The New York Fed could have reigned in Citigroup risks, but they did not do it." Angelides pointed out how Dodd-Frank would have sealed those gaps for one company in particular: Countrywide. By 2007, 25% of Countrywide's portfolio was made up of option adjustable-rate mortgages, where the borrower didn't even have to cover the accruing interest in his or her monthly payments. "Those kind of loans were a recipe for disaster," Shelby said. "Did regulators fail the American people?" "The Fed looked the other way," Angelides said. "They had a lot of this information and did not act." Angelides added the Office of the Comptroller of the Currency – Countrywide's initial regulator – began raising concerns. He pointed to an internal email at Countrywide, noting that executives were wary of the OCC suspicions and decided to switch regulators. It shifted to the Office of Thrift Supervision, which under Dodd-Frank will be absorbed by the OCC this summer. "The OCC had concerns. The OTS did not," Angelides said. "Dodd-Frank got rid of that regulatory shopping." Write to Jon Prior. Follow him on Twitter @JonAPrior.