In an article entitled "Halting Iran's Nuclear Weapons Program: Iranian Vulnerabilities and Western Policy Options" published this week by the Jerusalem Center for Public Affairs - run by former Israeli ambassador to the UN Dr. Dore Gold - Kuperwasser spells out what he believes is the only course of action that will stop Iran's race to nuclear power.

Thanks to technological sophistication, advances in producing raw materials as well as intermediate products and the improvement in protection of the program's components, the Western world is beginning to find it difficult to plan an effective strike against Iran's nuclear facilities, he said.

On Monday, The Washington Post revealed new satellite photos of Iran's enrichment facility at Natanz which showed the digging of a tunnel that analysts said could be used to hide and protect key nuclear components.

Iran, Kuperwasser said, was working on two parallel tracks - one at Natanz to enrich uranium and the plutogenic track being worked on at the Arak heavy water facility.

As long as Russia was not aligned with the United States, Kuperwasser said sanctions would not work on their own to stop Iran.

"For significant sanctions to be effective the world needs to at the same time threaten the use of military force," he said. "Iran needs to be made to understand that if the sanctions won't work, the world is prepared to use military force to stop the nuclear program."

He said Iran was preparing for the possibility of war, but that deep down the Islamic leadership did not believe that either the United States or Israel were in a position of strength that would enable them to launch such a complicated military operation. Iran, he said, was purchasing Russian air defense systems and was fortifying its nuclear facilities and moving key elements to underground bunkers in preparation for the possibility that its assessments were wrong and it would in the end be attacked.

"The Iranians are working around the clock on improving military capabilities and they are also moving centrifuges to underground facilities," he said.

Kuperwasser said that a real threat of military action - backed up by credible threats by world leaders as well as the deployment of a large military force to the region - could have the right effect in deterring Iranian leaders from continuing with their nuclear program.

A credible military threat combined with economic leverage had a chance at preventing the need for a future clash with a nuclear Iran and perhaps could also make it unnecessary to deal today with an Iran that is close to nuclearization, he said.