Here is a Globe and Mail op-ed by Ed Morgan, a professor of international law at the University of Toronto:
Reactions to the Israeli seizure of the Gaza-bound flotilla have shared two traits: They have virtually all invoked international law, and they have virtually all been marked more by their rhetorical excess than their knowledge of international law.
Israel’s critics have levelled the phrases “war crimes” and “piracy,” while its supporters have invoked the spectre of “terrorism” and “weapons of mass destruction.” But when it comes to the Law of the Sea, they may all be out to sea. While much of the international law that gets tossed around at the United Nations is up for ideological grabs, the rules of engagement at sea are among the few islands of stability. It therefore behooves us to have a look at the accepted law before going overboard on politicized interpretation.
Israel and Hamas are in a state of armed conflict. That much is clear to everyone who has looked at the situation, from the General Assembly to the Human Rights Council in its Goldstone Report, which has stressed the need to conform to the laws of war. Accordingly, the accusation of piracy is inapt, since under both customary law and Article 101 of the UN Convention on the Law of the Sea that applies only to acts done for private gain. Israel’s acts must be analyzed in terms of the law of naval warfare.
A blockade of an enemy’s coast is an established military tactic. It is recognized as a means at the Security Council’s disposal under Article 42 of the UN Charter where collective action is authorized. Likewise, as made clear in Article 539 of the Canadian Forces manual Counter-Insurgency Operations, it is an action that one belligerent can potentially impose on another, provided that the accepted conditions for the blockade are met.