According to Iran, there are good revolutions and there are bad revolutions. Tehran supported the uprisings in Egypt, Libya and Yemen last year, but on Thursday Iran’s highest authority, Ayatollah Ali Khamenei, reiterated his longstanding support for the Assad regime, saying his country is “strongly opposed” to any foreign intervention in Syria.The Ayatollah’s opposition made use of the standard boilerplate anti-Israel language, but commitment to Syria has little to do with Israel and everything to do with Iran. As the Christian Science Monitor put it, “Assad is a rare ally for Iran in an Arab world largely suspicious of Iranian ambitions for greater regional clout.” With that regime on the verge of collapse, Teheran is now facing the prospect of an Arab world united in opposition to Iran.Saudi Arabia has been particularly hostile, supporting western efforts to maintain sanctions by increasing their oil production to make up for any shortfall that may occur. The Saudis have even begun to resume normal relations with their hated rival, Iraq, to further up the pressure on the mullahs. As for Iraq, Baghdad isn’t feeling too receptive to Iranian overtures at the moment, given its relative weakness and fear of becoming entangled in Iran’s problems with the rest of the world.Iran is quickly running out of friends in the region. Should the Butcher of Damascus become the latest authoritarian domino to topple in the Middle East it would push Iran to the brink of regional and international isolation. Expect Iran to continue to hang tough with Syria—it has few other options.