Sunday's event at a campus north of Tel Aviv followed other high-profile Iran simulations in Israel and the United States in recent months. But it broke new ground by assuming the existence of what both countries have pledged to prevent: an Iranian bomb.
"Iranian deterrence proved dizzyingly effective," Eitan Ben-Eliahu, a retired air force commander who played the Israeli defense minister, said in his summary of the 20-team meeting.
Though the wargame saw Iran declaring itself a nuclear power in 2011, the ensuing confrontations were by proxy, in Lebanon. In one, emboldened Hezbollah guerrillas fired missiles at the Defense Ministry in Tel Aviv. That was followed by US and Israeli intelligence findings that Iran had slipped radioactive materials to its Lebanese cohort, to assemble a crude device.
Neither move drew Israeli attacks, though Ben-Eliahu said his delegation had received discreet encouragement from Arab rivals of Iran to "go all the way" in retaliating.
Instead, Israel conferred with the United States, which publicly supported its ally's "right to self-defense" and mobilised military reinforcements for the region while quietly insisting the Israelis stand down to give crisis talks a chance. "As far as the United States was concerned, Israel was trigger-happy. It sought to use the Hezbollah (missile) attack as justification for what the United States was told would be an all-out war," said Dan Kurtzer, a former US ambassador to Tel Aviv who played President Barack Obama.
Kurtzer voiced satisfaction with his team's response to the "dirty bomb,” which entailed cajoling UN Security Council powers into mounting an armed intervention against Hezbollah.
"Countries like China and Russia have their own terrorists, and don't want to see them getting nuclear weapons," he said.
"In certain circumstances, agile US diplomacy can actually work in this region, and it ends up not only leaving Israel in check but it also ends up (with Washington) leading a willing international coalition."
Those playing Iran and Hezbollah went as far as to question the very premise that Tehran would let the Lebanese fighters goad Israel into a potentially catastrophic fight, or give them nuclear know-how that would worry even sympathisers like Syria. Aharon Zeevi-Farkash, a retired Israeli intelligence chief acting as Iranian Supreme Leader Ali Khamenei, insisted Iran would regard its bomb as a means of "self-defense and strategic balance" - an allusion to Israel's own, assumed atomic arsenal. Such assessments are seldom voiced by Israel's rightist government, which describes a nuclear-armed Iran as a mortal danger. Where Israeli officials would once make veiled threats to strike Iran, now they often try to warn the West against accommodating their foe, which denies seeking atomic weapons.
In what appeared to signal government discomfort with the wargame, a senior Israeli defense official who had been due to attend withdrew at short notice. A Foreign Ministry spokesman said a written summary would be studied at government-level.
That left Tzipi Livni, the centrist head of Israel's opposition, as the most prominent observer of the IDC event.
"As leader of the free world, the United States has the responsibility of leading more effective sanctions that can turn around, absolutely, this shift from a process of stopping (Iran's nuclear aims) to a process of acceptance," she said.
While the simulation found no immediate international drive to tackle Iran, Kurtzer attributed this to passive factors such as US war-fatigue and complained of a failure to address ramifications such as a nuclear arms race among Arab powers.
Some of the participants - including those playing Israel, the Palestinians and Syria - saw an opportunity for renewed Middle East peacemaking that might head off Iran's ascendancy.
"This was tactical, but of course tactics can often serve real strategic interests, both for us and for the Americans," said Zalman Shoval, a former Israeli ambassador to Washington who acted as Prime Minister Benjamin Netanyahu.
