Michael Slackman profiles Mehdi Karroubi and his emergence as the key figure in the Iranian dissident movement:
Once a second-tier opposition figure operating in the shadow of Mir Hussein Moussavi, his fellow challenger in Iran’s discredited presidential election in June, Mr. Karroubi has emerged in recent months as the last and most defiant opponent of the country’s leadership. […]
But for all its success at preserving authority, the government has been unable to silence or intimidate Mr. Karroubi, its most tenacious and, in many ways, most problematic critic. While other opposition figures, including Mr. Moussavi and two former presidents, Mohammad Khatami and Ali Akbar Hashemi Rafsanjani, are seldom heard now, Mr. Karroubi has been unsparing and highly vocal in his criticism of the government, which he feels has lost all legitimacy.
The regime seems uncomfortable arresting Karroubi due to his long association with the Iranian revolution. That said, there’s relatively little a leader can do without followers. And as the excellent report “Accelerating Slide into Dictatorship: Human Rights in Iran since 12 June 2009″ details, the costs of being an average opposition supporter now look very high.