The history of the Islamic Republic is filled with cases of factions exploiting foreign policy to gain power against their domestic rivals. It is common for competing groups to sacrifice national interests — such as Iran's international credibility — to achieve their own goals.
During the Iran-Iraq war, U.S. President Ronald Reagan's national security adviser, Robert McFarlane, paid a clandestine visit to Iran with the approval of the country's highest authorities, to pursue a deal that would have been to Iran's advantage. But anti-American elements in the government leaked the news to an Arab newspaper, killing the deal and landing both the Reagan administration and the Iranian government in huge trouble.
Mir Hossein Mousavi, the former prime minister who now leads the opposition, spelled out the problem more than 20 years ago. On Sept. 5, 1988, he resigned in protest against then-President Ali Khamenei's interference in his duties. In his resignation letter, Mousavi complained that the "government's authority on foreign policy was taken away." He charged that "[military and intelligence] operations outside the country are taking place without the government's knowledge or orders. ... Only after an airplane is hijacked are we made aware of it. Only after a machine gun opens fire in one of Lebanon's streets and its noise echoes everywhere do we find out. Only after [Saudi police] find explosive material in Iranian pilgrims' baggage am I informed."