It was meant to be a crowning moment in which Iran put its own Islamic stamp on the Arab Spring. More than a thousand young activists were flown here earlier this week (at government expense) for a conference on "the Islamic Awakening," Tehran's effort to rebrand the popular Arab uprisings of the past year. But there was a catch. No one was invited from Syria, whose autocratic president, Bashar al-Assad, is a crucial Iranian ally.