During the Spanish American
War, the US Navy boarded two private fishing vessels flying the Spanish
flag, and captured them as prizes of war.
One of the vessels was named
The Paquete Habana.
The owners of the vessels sued
in US courts to regain their property.
They argued that customary
international law said that fishing
vessels were exempt from being captured in war.
They were commercial
fishermen, they were not a military target.
The US Supreme Court found
that the fishing vessels could not be taken as prizes of war.
The US Supreme Court found
that there was no specific US law defining a prize of war.
However, the Court found
that customary international law
exempted fishing vessels from being taken as prizes of war.
There are a number of
factors that determine if something is customary international law. In this case, the Court found that:
There was State practice by
a number of different countries that commercial fishing vessels were
exempt.
There was repetition of the
practice over time.
There was opinio juris that commercial fishing vessels were exempt.
Opinio juris is a subjective element that is used to
judge whether the practice of a state is due to a belief that it is
legally obliged to do a particular act.
This case lays out the
important factors that courts use to determine if something has become customary
international law.
Customary international
law can be thought of as a kind of
international common law.
It is something that's not explicitly defined anywhere, but everyone just
agrees to it.
