One of the most classic American political debates — state versus federal law — is surfacing again in the banking sector, as regulators work to put in place the financial reforms passed a year ago in Washington. At issue is whether state banking regulators will be undercut by their federal counterparts when it comes to consumer financial protection laws. Banks, state regulators and consumer advocates have been sparring in legalese-filled comment letters over the last month in response to rules proposed by the Office of the Comptroller of the Currency, which regulates national banks.