A unilateral Israeli strike on Iran's nuclear facilities would likely have dire consequences, including a regional war, global economic collapse and a major power clash.
For an Israeli campaign to succeed, it must be quick and decisive. This requires an attack that would be so overwhelming that Iran would not dare to respond in full force.
Such an outcome is extremely unlikely since the locations of some of Iran's nuclear facilities are not fully known, and known facilities are buried deep underground.
All of these widely spread facilities are shielded by elaborate air defense systems constructed not only by the Iranians, but also the Chinese and, likely, the Russians as well.
By now, Iran has also built redundant command and control systems and nuclear facilities, developed early warning systems, acquired ballistic and cruise missiles and upgraded and enlarged its armed forces.
Because Iran is well-prepared, a single, conventional Israeli strike - or even numerous strikes - could not destroy all of its capabilities, giving Iran time to respond.
Unlike Iraq, whose nuclear program Israel destroyed in 1981, Iran has a second-strike capability comprised of a coalition of Iranian, Syrian, Lebanese, Hezbollah, Hamas, and, perhaps, Turkish forces. Internal pressure might compel Jordan, Egypt, and the Palestinian Authority to join the assault, turning a bad situation into a regional war.
During the 1973 Arab-Israeli War, at the apex of its power, Israel was saved from defeat by President Nixon's shipment of weapons and planes. Today, Israel's numerical inferiority is greater, and it faces more determined and better-equipped opponents. After years of futilely fighting Palestinian irregular armies, Israel has lost some of its perceived superiority - bolstering its enemies' resolve.
Despite Israel's touted defense systems, Iranian coalition missiles, armed forces, and terrorist attacks would likely wreak havoc on its enemy, leading to a prolonged tit-for-tat.
In the absence of massive U.S. assistance, Israel's military resources may quickly dwindle, forcing it to use its alleged nuclear weapons, as it had reportedly almost done in 1973.
An Israeli nuclear attack would likely destroy most of Iran's capabilities, but a crippled Iran and its coalition could still attack neighboring oil facilities, unleash global terrorism, plant mines in the Persian Gulf and impair maritime trade in the Mediterranean, Red Sea, and Indian Ocean.
Middle Eastern oil shipments would likely slow to a trickle as production declines due to the war and insurance companies decide to drop their risky Middle Eastern clients. Iran and Venezuela would likely stop selling oil to the United States and Europe.
From there, things could deteriorate as they did in the 1930s. The world economy would head into a tailspin; international acrimony would rise; and Iraqi and Afghani citizens might fully turn on the U.S., immediately requiring the deployment of more troops.
Russia, China, Venezuela, and maybe Brazil and Turkey - all of which essentially support Iran - could be tempted to form an alliance and openly challenge the U.S. hegemony.
Iran may well feel duty-bound to respond to a unilateral attack by its Israeli archenemy, but it knows that it could not take on the United States head-to-head. In contrast, if the United States leads the attack, Iran's response would likely be muted.
If Iran chooses to absorb an American-led strike, its allies would likely protest and send weapons, but would probably not risk force.
While no one has a crystal ball, leaders should be risk-averse when choosing war as a foreign policy tool. If attacking Iran is deemed necessary, Israel must wait for an American green light. A unilateral Israeli strike could ultimately spark World War III.
Contact Reuveny, a professor in the School of Public and Environmental Affairs at Indiana University, at SPEA/ IU, 1315 E. 10th St., Bloomington, IN 47405.