Leading article: Israel's nuclear ambiguity

Given his determination to focus the world's attention on the perils of Iran's nuclear programme, Benjamin Netanyahu must have had very powerful reasons to pull out of next week's nuclear security summit in Washington. In fact, the Israeli Prime Minister had two of them.

The lesser one, probably, was his desire to avoid another meeting with President Obama – one that might have highlighted not Tehran's suspected drive to build a bomb, but the damaging rift with the US over Israel's continuing settlements expansion in East Jerusalem. More important however, we suspect, was Mr Netanyahu's fear that the 47-nation conference would have turned an unwelcome spotlight on Israel's own undeclared nuclear arsenal.

By all accounts, Turkey and Egypt planned to raise the issue of Israel's refusal to subscribe to the 1970 nuclear Non-Proliferation Treaty. This enables it to avoid international inspections, and thus maintain ambiguity about whether it has nuclear weapons. Israel is presumed to have anywhere between 80 and 200 such warheads, as an ultimate insurance policy against aggression.

But open acknowledgement would change the entire diplomatic equation in the region. Egypt and Turkey are leading a campaign for the Middle East to be declared a nuclear-free zone by the United Nations, not least because of their irritation with the double standards implicit in Israel's non-participation in the NPT.

Neither wants Iran to acquire nuclear weapons – a development that, if unchecked, would almost certainly set off a nuclear arms race in the region. This would make the Middle East even more dangerous than it is now, and increase the risk of weapons technology, even an actual weapon, falling into terrorist hands. This risk is at the top of the Washington summit agenda.

But it understandably rankles the entire Arab world that the West turns a complaisant eye to Israel's status as an undeclared nuclear power, while pressing other countries in the region to refrain from developing such technology. Not surprisingly, Iran makes this very argument to justify its own nuclear programme. One way and another, the crisis with Tehran will not be resolved without addressing Israel's own capability.