So the crisis has been foreseeable for decades; it would be automatically triggered by the emergence of a second nuclear power, friendly or unfriendly to the west. Iran is the unfriendliest possible, encouraging the widespread assumption that it alone is responsible for creating the crisis - and settling it. But is it?

It certainly isn't blameless. First, its nuclear arming would deal a major blow to an already fraying international non-proliferation regime. Second, it would involve a huge deceit. Third, the US divides actual or potential nuclear powers into responsible and irresponsible ones. Iran would be irresponsible, being already the worst of "rogue states".

Typically, a "rogue state", as well as being oppressive, ideologically repugnant and anti-American, unites an aggressive nature with disproportionate military strength, thereby posing a constant, exceptional threat to an established regional order. What could now more emphatically consign Iran to such company than its new president, with his calls to "wipe Israel off the map"?

Yet, in nuclear terms in the Middle East, Israel is the original sinner. Non- proliferation must be universal: if, in any zone of potential conflict, one party goes nuclear, its adversaries can't be expected not to. No matter how long ago it was, by violating that principle Israel would always bear a responsibility for whatever happened later. Second, its deceit was no less than Iran's, though, there being no non-proliferation treaty at the time, it was only the US it deceived. Mindful of what Israel's mendacity portended, the CIA warned in 1963 that, by enhancing its sense of security, nuclear capacity would make Israel less, not more, conciliatory to the Arabs; it would exploit its new "psychological advantages" to "intimidate" them.

Which, thirdly, points to the irresponsible use Israel has indeed made of it. Sure, it always justified it as its "Samson option", its last recourse against neighbours bent on destroying it. There is no such threat now; but if there was once, or will be again, the question is why.

A major part of the answer is that on most counts except hostility to the US Israel has always behaved like a "rogue state". It came into being as a massive disrupter of the established Middle East order, through violence and ethnic cleansing. Such a settler-state could only achieve true legitimacy, true integration into a still-to-be-completed new order, by restoring the Palestinian rights it violated in its creation and growth.

That, at bottom, is what the everlasting "peace process" is about. The world has a broad definition of the settlement lying at the end of it. It doesn't involve the full emancipation of an indigenous people that has been the norm in European decolonisation; only a compromise vastly more onerous for the defeated Palestinians than the Israelis.

But settlement never comes, because Israel resists even that compromise. Its nuclear power, on top of its already overwhelming conventional superiority, ensures that. Such irresponsible use of it is what Shimon Peres was alluding to when he said that "acquiring a superior weapons system would mean the possibility of using it for compellent purposes - that is, forcing the other side to accept Israeli political demands". Or what Moshe Sneh, a leading Israeli strategist, meant when he said: "I don't want the Israeli-Palestinian negotiations to be held under the shadow of an Iranian nuclear bomb." As if the Arabs haven't had to negotiate under the shadow of an Israeli bomb these past four decades.

There are three ways the crisis can go. The first is that Israel insists on, and achieves, the unchallenged perpetuation of its "original sin". For it isn't so much "the world", as President Bush keeps saying, that finds a nuclear Iran so intolerable, but the world on Israel's behalf; not the risk that Iran will attack Israel that makes the crisis so dangerous, but that Israel will attack Iran - or that the US will take on the job itself. In effect, Israel's nuclear arsenal, or the protection of it, has become a diplomatic instrument against its benefactor.

t is a legacy of America's own "original sin", that first, reluctant acquiescence in a nuclear Israel, subsequently turned into uninhibited endorsement of it by seemingly ever more pro-Israeli administrations. So here is a superpower, wrote the US strategic analyst Mark Gaffney, so "blind and stupid" as to let "another state, ie Israel, control its foreign policy". And, in a brilliant study, he warned that a US assault on Iran could end in a catastrophe comparable to the massacre of Roman legions at Cannae by Hannibal's much inferior army. For in one field of military technology, anti-ship missiles, Russia is streets ahead of the US. And Iran's possession of the fearsome 3M-82 Moskit could turn the Persian Gulf into a death trap for the US fleet. And sure enough, from the Bush administration itself, the first hints have been coming that, given the regional havoc Iran could indeed wreak, there may be nothing the US can do to stop it going nuclear.

This points to a second way the crisis could go - with Israel obliged to renounce its monopoly and the Middle East entering a cold-war-style "balance of terror". It could be a stable one. Clearly, like Israel, the mullahs would make irresponsible, political use of their nukes. But, like Israel's, Iran's nuclear quest is essentially defensive, even if not in quite the same fundamentally "existential" sense. Nothing could have more convinced it of the need for an unconventional deterrent than the fate of that other "rogue state", Saddam's Iraq, which the US had no qualms about attacking because it didn't have one.

The third way - Iran's abandonment of its nuclear ambitions - would stand its best chance of being accomplished if Israel were induced to do likewise; not just because reciprocity is the essence of disarmament, but because it would signify a fundamental change in America's whole approach to the region.

And that might have positive effects beyond the nuclear. "There is only one way," said the Israeli military analyst Ze'ev Schiff, "to avoid a nuclear balance of terror: to use the time left, while we still have a monopoly in this field, to make peace ... In the framework of peace, a nuclear-free zone can be established." But that is the wrong way round.

To make peace, as the CIA foresaw, Israel doesn't need the intransigence that absolute security brings, but the spirit of compromise that a judicious dose of insecurity might. A utopian notion perhaps, with the world now so focused on the villainy of Iran - yet better than a US onslaught that would add so thick a layer to an already mountainous deposit of anti-western feeling that Israel could barely hope ever to win acceptance in the region.

· David Hirst reported from the Middle East for the Guardian from 1963 to 2001 dhirst@beirut.com