What law identifies the principal authority for enforcing U.S. maritime safety and security regulations?

The Coast Guard and Maritime Transportation Act of 2004 serves as a critical piece of legislation that identifies the principal authority for enforcing U.S. maritime safety and security regulations. This act consolidated and updated various regulations that directly pertain to maritime safety and the responsibility of the Coast Guard in ensuring the security of U.S. waters and maritime operations. It provides the framework for the Coast Guard's roles, including enforcing safety standards, facilitating maritime commerce, and responding to maritime security threats.

The other laws mentioned have specific areas of focus but do not serve as the principal authority for the enforcement of maritime safety and security regulations in the comprehensive manner that the Coast Guard and Maritime Transportation Act of 2004 does. The Ports and Waterways Safety Act focuses on safety specific to ports and waterways, while the Homeland Security Act primarily concentrates on the overall security of the United States, including but not limited to maritime threats. The Magnuson Act is more related to fishery management and marine resource conservation. Thus, the Coast Guard and Maritime Transportation Act of 2004 distinctly establishes the Coast Guard's authority in enforcing regulations vital for maritime safety and security.