The Merchant Marine Act of 1920 - "The Jones Act"

The Merchant Marine Act of 1920 (P.L. 66-261) is a United States Fedearl statute that regulates maritime commerce in U.S. waters and between U.S. ports. Section 27, also known as the Jones Act, deals with cabotage (i.e., coastal shipping) and requires that all goods transported by water between U.S. ports be carried in U.S.-flag ships, constructed in the United States, owned by U.S. citizens, and crewed by U.S. citizens and U.S. permanent residents. The purpose of the law is to support the U.S. merchant marine industry.

Requests for waivers of certain provisions of the act are reviewed by the United States Maritime Administration on a case-by-case basis. The Obama administartion has not seen any need to waive the Jones Act as part of the response to the oil disaster in the Gulf of Mexico. (Wiki, Deepwater Horizon Response)