A changed Iran can influence the entire Middle East

The now-joined struggle for Iranian hearts and minds is where the universal battle of ideas — democracy vs. tyranny — meets the dictates of Middle Eastern geography. Whereas Iraq, Syria, Saudi Arabia and other Arab states are puzzle pieces carved out of featureless desert, with no venerable traditions of statehood, the roots of a great Persian power occupying the Iranian plateau date to the Achaemenid, Parthian and Sassanid empires. With nearly 70 million people occupying the tableland between the oil-rich Caspian Sea and the oil-rich Persian Gulf, Iran is the Muslim world's universal joint.

Iranian power, both soft and hard, is felt from the Mediterranean to the Indus. Indeed, Iran's influence in southern Lebanon and Gaza is part of a historical tradition of empire and Shiite rule. By puncturing the legitimacy of the clerical authority, the demonstrations in Tehran and other cities have the capacity to herald a new era in Middle Eastern and Central Asian politics.

Iran's governing institutions, however illiberal their current intent, are structurally sounder than most in the Arab world. When the shah was toppled, anarchy did not ensue: Within weeks, a Shiite bureaucratic apparatus filled the void. That sophisticated network reflected not just religion but also Iranian high culture.

The Iran of the ayatollahs was never a one-dimensional tyranny such as Saddam Hussein's Iraq; it is a complex system with an elected parliament and chief executive. Likewise, Iran's democracy movement is strikingly Western in its organizational discipline and its urbane use of technology. In terms of development, Iran is much closer to Turkey than to Syria or Iraq. While the latter two live with the possibility of implosion, Iran has an internal coherence that allows it to bear down hard on its neighbors. In the future, a democratic Iran could be, in a benevolent sense, as influential in Baghdad as the murder squads of a theocratic Iran have been in a malignant sense.

Iran is so central to the fate of the Middle East that even a partial shift in regime behavior — an added degree of nuance in its approach to Iraq, Lebanon, Israel or the United States — could dramatically affect the region. Just as a radical Iranian leader can energize the "Arab street," an Iranian reformer can energize the emerging but curiously opaque Arab bourgeoisie. This is why the depiction of presidential candidate Mir Hossein Mousavi as but another radical, albeit with a kinder, gentler exterior than President Mahmoud Ahmadinejad, completely misses the point.