Law of the Flag Law and Legal Definition
Law of the flag is a principle of maritime and international law that the sailors and vessel will be subject to the laws of the state corresponding to the flag flown by the vessel. The law of the flag doctrine is chiefly applicable to ships on the high seas, where there is no territorial sovereign. With respect to ships in foreign territorial waters it has little application beyond what is affirmatively or tacitly permitted by the local sovereign.
The traditional statement of the law of the flag doctrine provides that a merchant ship is part of the territory of the country whose flag she flies, and that actions aboard that ship are subject to the laws of the flag state. The law of the flag doctrine does not mandate that anything that occurs aboard a ship must be handled by the flag state. In fact, the United States Supreme Court has recognized that the law of the flag doctrine does not completely trump a sovereign's territorial jurisdiction to prosecute violations of its laws. [United States v. Kun Yun Jho, 534 F.3d 398 (5th Cir. Tex. 2008)]