What are the permissible responses to suspicions of non-innocent passage of warships through the territorial waters of another nation? According to Article 19(2)(c) of the United Nations Convention on the Law of the Sea, "any act aimed at collecting information to the prejudice of the defence or security of the coastal State" within territorial waters renders the passage non-innocent. However, intelligence gathering per se within the territorial sea is not prohibited by the convention.

Article 25(1) provides that "(t)he coastal State may take the necessary steps in its territorial sea to prevent passage which is not innocent". This authority is qualified by Article 32 which states: "With such exceptions as are contained in subsection A and in articles 30 and 31, nothing in this Convention affects the immunities of warships and other government ships operated for non-commercial purposes." Warships, as extensions of sovereign power, are immune from the civil and criminal jurisdiction of other nations.

If the USS Pueblo had been in the territorial waters of North Korea, would the seizure of the USS Pueblo have been allowable under international law? According to the 1982 Convention, no. Although the coastal state has limited authority to regulate the passage of warships through the territorial sea, the remedy for non-compliance is stated in Article 30: "If any warship does not comply with the laws and regulations of the coastal State concerning passage through the territorial sea and disregards any request for compliance therewith which is made to it, the coastal State may require it to leave the territorial sea immediately".

However, the power to prohibit intelligence gathering is not within the limited authority granted to the coastal state by the convention. And the remedy provided by Article 30 seemingly does not apply to non-innocent passage which does not violate the laws and regulations of the coastal state. So what can a coastal state do when it suspects a foreign warship of gathering intelligence in its territorial sea? How does the coastal state prove that a warship is gathering intelligence? By inference? (type of ship, for instance). Is an attack on a warship suspected of intelligence gathering a response proportionate to the threat posed by the ship?

20th Anniversary Interview with Peter Bucher, Commander of the USS Pueblo (ABC, 1988)