The U.S. Supreme Court has ruled that banks are subject to state, as well as Federal regulation. This allows state Attorney Generals like New York's Andrew Cuomo to regulate banks.
Why shouldn't this be the case. "All" banking is "local," right? Banks are part and parcel of the states within which they operate. Consequently, the states should be allowed to force the banks in their midst to address their concerns.
The push for state banking goes back to the time of President Andrew Jackson, a states rights man who nevertheless wanted to preserve the Union. His main opponent was Philadelphia banker Nicholas Biddle, who wanted Federally chartered banks. Jackson won, and for 80 more years, state banks held sway in their respective states.
Many banks are large enough to be regulated at the Federal level. But they should also be answerable to the states. The alternative, as fellow blogger Michael Davis pointed out, could be a choice of regulator between Barney Frank and Bozo the clown. And that's not much of a choice.