In 1981, Israel destroyed Iraq’s nuclear reactor at Osirak, declaring it could not live with the chance the country would get a nuclear weapons capability. In 2007, it wiped out a North Korean-built reactor in Syria. And the next year, the Israelis secretly asked the Bush administration for the equipment and overflight rights they might need some day to strike Iran’s much better-hidden, better-defended nuclear sites.

They were turned down, but the request added urgency to the question: Would Israel take the risk of a strike? And if so, what would follow?

Now that parlor game question has turned into more formal war games simulations. The government’s own simulations are classified, but the Saban Center for Middle East Policy at the Brookings Institution created its own in December. The results were provocative enough that a summary of them has circulated among top American government and military officials and in many foreign capitals.

For the sake of verisimilitude, former top American policymakers and intelligence officials — some well known — were added to the mix. They played the president and his top advisers; the Israeli prime minister and cabinet; and Iranian leaders. They were granted anonymity to be able to play their roles freely, without fear of blowback. (This reporter was invited as an observer.) A report by Kenneth M. Pollack, who directed the daylong simulation, can be found at the Saban Center’s Web site.