the State to enforce the provisions of this Act, as the Secretary considers appropriate. 11. Effect on State authority (a) In general Except as provided in subsection (b) and as necessary to implement an agreement entered into under section 10, no State or political subdivision thereof may adopt or enforce any statute, regulation, or other requirement of the State or political subdivision with respect to— (1) a discharge into navigable waters of the United States from a commercial vessel of ballast water