Quote Originally Posted by slapout9 View Post
It didn't help matters that the ship was in International waters either, at that point I don't think Israel had a legal right to do anything, which certainly cast them in the role of the aggressor. May not have made any difference in the end, but they would (Israel) had a much stronger case if they were clearly in Israeli territorial waters.
It's my reading of international law is that states can insist on port inspection of cargos on neutral ships destined for a blockaded port, and board ships (or worse) that fail to comply, even in international waters. You'll find a summary of the relevant laws of war in the San Remo Manual on International Law Applicable to Armed Conflicts at Sea, on the ICRC website. According to that summary:

98. Merchant vessels believed on reasonable grounds to be breaching a blockade may be captured. Merchant vessels which, after prior warning, clearly resist capture may be attacked.

...

118. In exercising their legal rights in an international armed conflict at sea, belligerent warships and military aircraft have a right to visit and search merchant vessels outside neutral waters where there are reasonable grounds for suspecting that they are subject to capture.
Then again, neutrals aren't explicitly required to be cooperative either, so perhaps there's nothing technically illegal about whacking the boarders with axe handles!

The law does require, however, that a blockade not have as its primary target the civilian population:

102. The declaration or establishment of a blockade is prohibited if:

(a) it has the sole purpose of starving the civilian population or denying it other objects essential for its survival; or
(b) the damage to the civilian population is, or may be expected to be, excessive in relation to the concrete and direct military advantage anticipated from the blockade.

103. If the civilian population of the blockaded territory is inadequately provided with food and other objects essential for its survival, the blockading party must provide for free passage of such foodstuffs and other essential supplies, subject to:

(a) the right to prescribe the technical arrangements, including search, under which such passage is permitted; and
(b) the condition that the distribution of such supplies shall be made under the local supervision of a Protecting Power or a humanitarian organization which offers guarantees of impartiality, such as the International Committee of the Red Cross.
A broader argument can also be made that the primary purpose of the Israeli blockade of Gaza is collective punishment of the civilian population, which would violate IHL.

The lawyers can no doubt add additional layers of complexity