Another Klingon War Crime
Not only do the Klingons violate interstellar law by starting wars, they regularly violate interstellar laws of warfare. Among the many wrongs that the Klingons are committing, they also owe us a new dilithium processing unit for the one they stole from the Shenzhou. Anciently, when wars were justified by being the winner, winners were allowed to take the spoils of war. But even the Klingon legal system does not support the actions that they have taken.
Their legal system stems from the writings of one lawyer of theirs who defended the right of ships (on sea) to take whatever they wanted. Earth used to operate like that, and an ancient lawyer there said that "war is just for the very reason that it tends toward the attainment of rights; and in seizing prize or booty, we are attaining through war that which is rightfully ours."1 Presumably the Klingons will defend their actions based on an idea that the Federation somehow wronged them.
But the Federation, and most of the known galaxy has long seen these sort of acts as aggression and piracy. We've moved on from discerning between Privateers and pirates. On earth it has been a peremptory norm of international law for centuries,2 so much so that it has hardly changed since we've started making faster-than-light ships. The only difference is that space is bigger than the ocean. Under our law, one could claim salvage to a derelict ship, but I won't even get into that because one huge exception to that is if the salvaging party CAUSED THE SHIP TO BE DERELICT.
1 see also Hugo Grotius, De Jure Prae Commentarius, 68, 180, translated by Gwladys L. Williams; see also The Klingon Translation of the above work "paq chut tev Soq 'ej." ↩
2 See M. Sherif Bassiouni, "International Crimes: Jus Cogens and Obligatio Erga Omnes," Law and Contemporary Problems Vol 59: No. 4 (1997).↩