For decades, Israel has demonstrated that it conceives of and uses its nuclear program responsibly to deter its enemies, and it never caused Egypt, Jordan or Saudi Arabia to seek a nuclear program.
In contrast, Iran has consistently portrayed its program as an offensive agent of Israel's annihilation, as the widow of one nuclear scientist recently assassinated made clear. Since Iran's program existentially threatens Israel, Israel must possess the means to deter or defeat the realization of that threat. Nowhere is this difference between Israel's and Iran's programs highlighted more than by Saudi officials who have stated Iran's, not Israel's, program is the red line which provokes Riyadh's quest for nuclear weapons.
Nor would an Israeli offer of disarmament defuse tensions. Iran maintains that only threats and violence cower Israel. An Israeli attempt to seduce Tehran into surrendering its ambitions by accepting regional disarmament would only confirm Iran's belief that its belligerence and aggressive behavior toward Israel achieved what no other leaders could. So, rather than moderate Tehran's ambition, it would reward Iran's aggression, confirm its strategy of threats, and encourage it to accelerate.
Regarding the regional proliferation environment, Israel's nuclear program is only one of the problems with weapons of mass destruction. Israel has long accepted the idea of a W.M.D.-free zone, but only linked to solidly verifiable agreements on biological weapons, which are incapable of being verifiably controlled. For Israel to disarm without an effective biological control regime is to leave Israel asymmetrically vulnerable to a W.M.D. attack.
Israel relies on its ultimate weapon to guarantee its numerical inferiority will not translate into destruction very much like numerically inferior NATO forces refused to sign away their rights on first-use of nuclear weapons to guarantee Warsaw Pact armies could not translate their numerical superiority into victory.
The West has anchored its vision of Arab-Israeli peace to land-for-peace. As Israel withdraws from territories, it surrenders security and strategic depth for which only strategic power namely maintaining its nuclear arsenal can compensate. Repeatedly, Israel's allies and neighbors traded acquiescence in its nuclear status for Jerusalem's strategic confidence and willingness to trade land for peace, which yielded, among other things, the Egyptian-Israeli peace treaty.