The ruling regime in Tehran is enforcing its authority through Stalinist show trials.  That, at least, is the opinion of The Wall Street Journal, with its piece here. 

Arthur Koestler's Darkness at Noon centers around a character based on Nikolai Bukharin, the head of the Comintern and close associate of Lenin who was, along with many of his Old Bolshevik colleagues, purged on Stalin's orders in the 1930s.  Now Iran, like the Soviet Union in the days of Stalin's show trials, also has a prominent revolutionary insider who finds himself, and the movement that he leads, on the outside of the political system.

In the 1930s, the economic crisis of the Great Depression caused many intellectual and political elites in the West to look sympathetically on the Communist regime in the Soviet Union.  That was a horrendous decision, one which gave political cover to Stalin to continue with the Great Purge, and perpetrate genocides against ethnic minorities.  Obama has certainly not been overly sympathetic to Iran.  But he risks doing so, and thereby justifyng not only Iran's Stalinist persecutions but the persecutions at work in other societies, if he becomes too willing to deal with harsh regimes, simply for the sake of having something to show for his efforts to resolve difficult challenges facing the global economy and the non-proliferation of nuclear weapons.