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.
Treaty on the Non-Proliferation of Nuclear Weapons
Israel has a long-standing policy of deliberate ambiguity with regards to its nuclear program (see List of countries with nuclear weapons). Israel has been developing nuclear technology at its Dimona site in the Negev since 1958, and some nonproliferation analysts estimate that Israel may have stockpiled between 100 and 200 warheads using reprocessed plutonium. The position on the NPT is explained in terms of "Israeli exceptionality", a term coined by Professor Gerald M. Steinberg, in reference to the perception that the country's small size, overall vulnerability, as well as the history of deep hostility and large-scale attacks by neighboring states, require a deterrent capability.