The ships that were intercepted by Israel, however, were carrying aid. The law or armed conflict requires that blockading states allow aid through to the civilian population; however, the blockading state may control the channel through which aid is delivered, and that is what Israel has been doing.
The authority to intercept vessels and control aid deliveries, however, is available only in a lawful blockade. To be lawful, a blockade must not be implemented where the damage to the civilian population is excessive in relation to the concrete and direct military advantage anticipated from the blockade, and this is where Israel’s legal position is open to question.
The BBC has reported UN agencies as saying that insufficient aid is reaching Gaza, possibly less than one quarter of daily needs. This raises serious questions about the underlying legality of the blockade.
The relevant rules of armed conflict prohibit intentionally starving the civilian population and require that humanitarian supplies essential to survival must be allowed to pass, albeit subject to certain controls by the blockading power.
To maintain a population at a level just above the bare minimum needed for survival might arguably be within the strictest letter of the law, but could never seriously be thought consistent with its spirit.
Calls for the immediate cessation of the blockade may well have a good case in law as well as in humanitarian policy.