In the letter, Haniyeh claims that Hamas' terror is not only not prohibited, but a "right" under international law.
The letter says:
The rules of international humanitarian law have contributed to strengthening the legal status of the resistance and national liberation movements against the occupation, and to legitimizing their resistance activities to achieve their right to self-determination as mentioned in the First Additional Protocol to the Geneva Conventions, in particular article 1 / paragraph 4,: "The situations referred to in the preceding paragraph include armed conflicts in which peoples are fighting against colonial domination and alien occupation and against racist régimes in the exercise of their right of self-determination, as enshrined in the Charter of the United Nations.”The quote from the Additional Protocol refers to the idea that ALL armed groups must adhere to the international laws that protect civilian war victims (the preceding paragraph.) Meaning that it says that Hamas - if it is to be regarded as a freedom fighting group - is violating international law by shooting rockets to Israel, the exact opposite of what Haniyeh claims.
Hamas is a Palestinian national liberation movement that seeks by all means to defend its people in order to achieve their basic rights. This comes within the context of the legitimate defense and response to the continuous aggression against the Palestinian people. This right is guaranteed by Article 51 of the Charter of the United Nations, which represents a solid basis for the legitimacy of the struggle of the Palestinian people, individually and collectively, for independence and self-determination.Article 51 says "Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain international peace and security." Shooting rockets at civilians is not "self defense" in any universe.
He also quotes several non-binding General Assembly resolutions that from the early 1970s that say that people under colonial subjugation have the right to resist "by all necessary means," which never includes terrorism, except to Palestinians and their fans. Of course, Israel is not a colonialist state to begin with, but the idea that international law allows Hamas-style terror attacks is absurd.