Israel's concern about the spectre of a nuclear Iran has now degenerated into a crisis of confidence concerning the United States. Prime Minister Binyamin Netanyahu has embarked on a campaign to force President Barack Obama to set a red line that Iran must not cross, lest it risk unleashing an American military response. Implicit threats of a unilateral Israeli attack, together with conspicuous meddling in the US presidential election campaign, have compounded Netanyahu's effort to twist Obama's arm.

Netanyahu and Defence Minister Ehud Barak thus regard an attack on Iran as a major strategic move aimed at the broader Middle East, which implies that they would not discount a military campaign that goes well beyond surgical air strikes

As a result, the US, though certainly better equipped than Israel for a war to ensure that Iran forever abandons its nuclear ambitions, could nonetheless conclude that that objective is simply too costly. The recent report by The Iran Project, whose signatories include the former US national security advisers Brent Scowcroft and Zbigniew Brzezinski, concluded that an American military attack on Iran could only delay its nuclear programme for up to four years.

To guarantee that Iran never acquires a nuclear bomb, the US would need to maintain military pressure on Iran for several years. And, if forced to impose regime change as the ultimate solution to the dilemma, the report assumes that this would require military occupation, which would entail a commitment of resources and personnel greater than what the US invested in the Iraq and Afghanistan wars combined.