Iran's complex and unusual political system combines elements of modern Islamic theocracy with democracy, as a network of unelected institutions are controlled by a supreme leader who is countered by a president and parliament elected by the people. When Ayatollah Ruhollah Khomeini first established the theocracy after toppling the shah, one of the first things he did was set up a task force to examine how vulnerable his regime was to a takeover. This paranoia has been the key to the regime's survival over the past 25 years. "If there is anything the Islamic regime fears most, it is being toppled," said a high-ranking defense official. "This is its biggest nightmare." One of the first things the mullahs did after gaining control of the government was to duplicate the military. There is the official Armed Forces with a large navy and air force, and the Islamic Revolutionary Guard which also has its own navy and air force and is in charge of the Shihab ballistic missile program. While there are free elections for parliament, elections that brought Holocaust denier Mahmoud Ahmadinejad to power, the real decisions are made by the supreme leader, Ayatollah Ali Hoseini Khamenei, appointed to the post following Khomeini's death in 1989. The question is, whose finger would be on the nuclear button? If Iran succeeds in developing nuclear weapons, who would make the decision whether they would be used or not? Ahmadinejad, the radical president? Or Khamenei, the supreme leader? According to the senior defense official, whose job is to closely monitor events in Iran, the decision is not up to one person but would involve a small, close-knit group, including Ahmadinejad and Khamenei as well as the energy and defense ministers, both former officers in the Revolutionary Guard. A former mayor of Teheran, Ahmadinejad, Israeli intelligence says, was involved in the takeover of the US Embassy in 1979. He has called for Israel to be "wiped off the map" and most recently held a conference in Teheran described as a meeting of Holocaust deniers. Israeli officials breathed a sigh of relief last month after Ahmadinejad's ally, the ultra hardliner Ayatollah Mohammad-Taqi Mesbah Yazdi, failed to dominate in the elections for the Assembly of Experts, the council that filters all candidates for parliament. In the last elections, it disqualified 220 candidates and in effect threw out the reformists. "Yazdi is one of the most radical people in Iran today," the official said. "He is also Ahmadinejad's spiritual mentor and has a great deal of influence over him." He noted that while Khamenei is certainly anti-Israel and a radical, he is more moderate than Ahmadinejad. "The president's anti-Israel rhetoric and focus on the Holocaust does not make Khamenei happy," he said. Khamenei, he added, has a more pragmatic take on international relations, but is almost helpless in face of Ahmadinejad's high popularity among the public. A more remarkable aspect of Ahmadinejad's ideology is his devotion to the hidden imam, a messiah-like figure in Shi'ism who will appear at the end of days. He believes that his government needs to prepare the country for his return. One of the first decisions of Ahmadinejad's government was to invest millions of dollars in renovating the Jamkaran Mosque, where the devout drop notes for the hidden imam into a holy well. As mayor of Teheran, he invested millions in expanding a main thoroughfare it is believed the imam will use when he returns. In a recent interview on CNN, former prime minister Binyamin Netanyahu compared Ahmadinejad to David Korush, leader of the Branch Davidians from Waco, Texas. "It's the cult of the Mahdi, a holy man that disappeared a thousand years ago and the president of Iran believes that he was put here on Earth to bring this holy man back in a great religious war between the true Muslim believers and the infidels," Netanyahu said. "Ahmadinejad, the president of Iran, is first trying to develop nuclear weapons and then going about his mad fantasy of global conflict."