During Prohibition, the waters off the American coast became a battleground between federal agents and daring smugglers. Among the most famous rum-runners was the SS I'm Alone, a Canadian-registered wooden schooner fitted with powerful diesel engines. On March 20, 1929, the US Coast Guard cutter Dexter spotted the I'm Alone lingering near the coast of Louisiana.
When the schooner refused to stop for inspection, a chase began that stretched over 200 nautical miles into the Gulf of Mexico, far beyond US territorial waters. On March 22, the Dexter opened fire, riddling the I'm Alone with deck gun shells until it sank, resulting in the death of one crew member and the arrest of the rest. Canada erupted in protest, arguing that the United States had committed an act of war by sinking a foreign vessel on the high seas.
The US defended its actions using the legal doctrine of hot pursuit, claiming that a chase initiated in territorial waters permitted force anywhere. The dispute was submitted to an international arbitration commission. In 1935, the commissioners ruled that while hot pursuit was valid under international law, sinking the vessel was an excessive and illegal use of force.
The US was ordered to pay a formal apology and financial compensation to Canada, cementing strict legal limits on maritime law enforcement outside national boundaries.