A look at the legislative history does not support the notion of a subjective, political exemption for politically-motivated pirates.
Kevin Jon Heller’s argument that political motives are excluded from piracy rests less on the Law of the Sea Treaty itself than on its intellectual predecessors, the League of Nations Report of 1927 and the Harvard Draft Convention of 1932. The ILC Commentary to the Law of Sea Treaty specifically endorses the latter, saying that “in general” it agrees with the Draft Convention (it does not provide such deference to the former.
The Harvard Draft supports the lack of any subjective, motive-based inquiry. Here is exactly what it says in its commentary on the “private ends” part of the definition of piracy:
[A]lthough it is true that the typical pirate of fiction and tradition was an indiscriminative plunderer, expediency and not traditional epithets or the fancy of traditional concepts should direct the definition of the common jurisdiction over piracy, and every consideration of certainty in prosecution and of assured protection in places outside the territory of all states argues that the jurisdiction to seize and to punish a robber or a killer for private ends should not depend on whether the offender had by acts or words displayed an intent to plunder or slay only once or oftener, or on whether he intended to attack only the
citizens of certain states and their ships and other property, or to prey on the people and commerce of all nations indiscriminately. Such matters of collateral intent of an offender (often uncertain and indistinct) and of his transactions other than those involved in the case at hand, are very unsatisfactory as elements in a basis of state jurisdiction.
On the other hand, the language in the Draft that Prof. Heller says best supports his position does not come from the commentary on “private ends,” or indeed from the definition of piracy at all (contained in Art. 3). Rather, it comes from the commentary on Art. 14, which is not defining, or even discussing piracy at all, but rather the authority of states with traditional jurisdiction to apply non-piracy law.
Having looked further through the Committee’s work, I see no hint of an exclusion of political motives, and several pieces of evidence suggesting it was included.
The Commission’s final Commentary to the definition of piracy explained: “The intention to rob (animus furandi) is not required. Acts of piracy may be prompted by feelings of hatred or revenge, and not merely by the desire for gain.” The argument for Sea Shepherd is that they are not motivated by negative feelings, but by positive ones. Of course “hatred and revenge” are only illustrative – and quite typical of political violence. The language about “hatred and revenge” borrows from the League of Nations Committee of Experts for the Progressive Codification of International Law had to say in 1927. That document goes on the exclude “purely political motives” from piracy. Notably the ILC Commentary does not reference or endorse that second limitation. Quoting part of the 1927 report but not other relevant parts suggests the exclusion of the latter.
Let us now consider the proceedings leading up to the final text. At the May 8, 1956 meeting, Sir Gerald Fitzmaurice and others expressed some concern that “merchant vessels” could in wartime “seeking to acquire, quite inadmissibly, the status of warships by hoisting a naval flag in order to board, capture, or sink other vessels, after which they would revert to their former status of merchant ships.” Thus the general immunity of warships, and their exemption from piracy, had to strictly be limited to real, regularly constituted warships. The relevant point for our purpose is that if political purposes were enough to create immunity for a private vessels, a merchant vessel would have no need to redress itself to raid enemy commerce in wartime; such acts are by definition political. Yet in the view that piracy is the lack of public status, such concerns make sense.
The key aspect of private ends is the lack of public authority As Fitzmaurice commented at the May 9, 1956 meeting of the Commission: “The Commission’s conception had been that piracy was essentially an act committed by a ship’s company or persons acting on their own authority, thereby excluding warships.” He thus supported extending the piracy exemption to government ships other than war ships, since they also operated under public authority.
On a side note, I should add that I’m quite surprised and amused by the intensity of feeling on this issue. I wish there was as much sympathy for Ali, a guy who may spend his life in federal prison for something that isn’t piracy.) I must admit, I don’t have a TV, and do not know anything about the heroic depiction of Sea Shepherd. But Ali got a very sympathetic turn in Stolen Seas.