Throughout the 20th century, commercial gambling was strictly illegal in most U. S. states, but offshore operators discovered a lucrative legal loophole: the traditional three-mile limit.
Dating back to the 17th-century 'cannon-shot rule,' international law recognized a nation's sovereign territorial waters as extending three nautical miles from its coastline. Beyond that three-mile boundary lay the high seas, where local state and federal gambling prohibitions ceased to apply. Capitalizing on this legal boundary, entrepreneurially minded boat operators launched 'cruises to nowhere'—short boat trips designed solely to ferry passengers past the three-mile mark.
Once the vessel crossed the invisible maritime line, ship captains would announce that the offshore casino was open, allowing guests to play roulette, craps, and slot machines in international waters legally. States fought back through various legal maneuvers, including restricting ship access to state ports, enforcing state laws on shore-side ticket sales, and utilizing federal laws like the Johnson Act of 1951, which prohibited gambling devices on U. S.
-flagged vessels unless authorized by state legislation. Nevertheless, gambling ships flourished along the coasts of California, Texas, Florida, and New York for decades until states altered their tax codes and maritime jurisdictional boundaries expanded to 12 nautical miles under modern international treaties.