Oops, correction .. Fatah obviously should be Fatwa in
"then there was the Fatah by Khamanei against the development of nuclear weapons .. if it was broken it would be a real blow to his authority..."
Fatwas
As a Grand Ayatollah (disputed or not), Khamenei has issued thousands of fatwas in answer to questions from Shi'a petitioners, "on everything from Islamic law to betting on basketball, student loans to children in day care with non-Muslims, women on motorcycles to staying in hotels used by Buddhists". He has ruled against the wearing of neckties and the listening to music and news from foreign sources, but not nose piercing (as long as adornments are covered).
In 2010, Imam Khamenei issued a fatwa which bans any insult to the companions of Muhammad as well as his wives. This fatwa is a great effort to make a peace between two largest sects in Islam : Sunni and Shia[citation needed].
Fatwa against nuclear weapons
Khamenei with Major General Mansour Sattary (1948 - 1995) former Commander of Islamic Republic of Iran Air Force.
Ayatollah Ali Khamenei has issued a fatwa saying the production, stockpiling and use of nuclear weapons was forbidden under Islam. The fatwa was cited in an official statement by the Iranian government at an August 2005 meeting of the International Atomic Energy Agency (IAEA) in Vienna.
Iran's nuclear program has been a subject of international debate for decades. The Iranian government claims the purpose of its nuclear development is to produce electricity, while some western countries accuse it of trying to create nuclear weapons.