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.
Nuclear proliferation
In May 1998 India and Pakistan each exploded several nuclear devices underground. This heightened concerns regarding an arms race between them, with Pakistan involving the People's Republic of China, an acknowledged nuclear weapons state. Both countries are opposed to the NPT as it stands, and India has consistently attacked the Treaty since its inception in 1970 labeling it as a lopsided treaty in favor of the nuclear powers.