Nuclear triad
Israel is known to have nuclear-capable aircraft and land-base missiles, with the addition of nuclear-armed submarines this would mean that they now have a full triad of land-, air-, and sea-based nuclear delivery systems some of which would be invulnerable to a first strike by an enemy for the first time in their country's history. No other nation in the Middle East in known to be in possession of nuclear weapons, even though Iran, Iraq, Syria and Libya have started development programs that were never completed.
Southeast Asian Nuclear-Weapon-Free Zone Treaty
The treaty includes a protocol under which the five nuclear-weapon states recognized by the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), namely China, the United States, France, Russia and the United Kingdom (who are also the five permanent members of the United Nations Security Council) undertake to respect the Treaty and do not contribute to a violation of it by State parties. None of the nuclear-weapon states have signed this protocol.