On one side, a Turkish draft resolution at the UN Security Council described the attack as a violation of international law. On the other, Israel’s foreign ministry insists that international maritime law prohibits boats from entering an area subject to a maritime blockade and that vessels attempting to violate this may be captured or even attacked.
The debate is focusing global attention on the Israeli economic blockade of the Gaza Strip like never before, with questions being raised about the morality and legality of a three-year old blockade that Israel says is vital to its security but has led to medicine shortages, power outages, and, critics say, unnecessary deaths in the impoverished strip.
Mr. Guilfoyle says that under the international Law of Armed Conflict a state that has legally established a blockade can enforce it by boarding vessels in international waters that it reasonably expects might breach the blockade.
But a blockade itself is illegal, he says, "if it will cause excessive damage to the civilian population in relation to the military advantage gained... so therefore intercepting a vessel on the high seas to support or enforce the blockade would not be lawful.”
Israel says the blockade is necessary to protect if from rocket fire, but it has also led to economic collapse in Gaza, where the employment rate is now over 40 percent and the quality of medical care is deteriorating. Gazans say they can't see how prohibiting the import of fishing lines or canned goods – two of the items on Israel's banned list – enhances Israel's security, and conclude instead that a policy of collective punishment is being pursued against Gaza's people for having elected the Islamist Hamas movement to govern them.
Another issue is that the Mavi Marmara, on which at least nine people (including four Turks) died after Israeli troops stormed the vessel, was flying under a Turkish flag.
“Since the ship was flying a Turkish flag it was only subject to Turkish jurisdiction,” says Daniel Machover, a co-founder of the London-based lawyers for Palestinian Human Rights (LPHR). He says that while the Geneva High Seas Convention permits warships to interfere with ships flying the flag of another state in limited circumstances, such as if the vessel is engaged in the slave trade or piracy, no such factors apply in this case.
Mr. Machover's organization argues that since the initial boarding of the Mavi Marmara was “likely” to have been illegal, its civilian passengers had the right to defend themselves against the invading soldiers.
Israeli authorities have meanwhile cited International Law provisions applicable to armed conflict at sea. They says that merchant vessels flying the flag of neutral states in neutral waters can be intercepted if they "are believed on reasonable grounds to be carrying contraband or breaching a blockade....”
So what next?
Israel already faces legal action at home. A group of Israeli lawyers petitioned Israel's high court hours after the operation, calling it "an act of piracy" involving hijacking, robbery, wrongful arrest, and kidnapping.
The lawyers cite a number of precedents, including the so-called Lotus case of 1927, relating to an incident in which eight Turks died when a French ship collided with a Turkish vessel in international waters. The judicial branch of the UN’s predecessor, the League of Nations, ruled against France a year after the incident.
The other precedent they cite is the 1804 Murray vs. Charming Betsy case, in which a court ruled that the US Army cannot seize goods that are not for military use in international waters, even during wartime.
Separately, Turkish prosecutors are examining possible legal action under their country’s penal code.
Israel's attorney general Yehuda Weinstein said that all of the nearly 700 activists detained will be deported by the end of the day. He told the Associated Press that he has decided not to prosecute any of the activists. Israeli officials had earlier said they were considering prosecuting about 50 people believed to be involved in violence against Israeli soldiers.
(This story was edited after posting to correct Douglas Guilfoyle's institution. He is at University College London).