SERGEI SUPINSKY/AFP/Getty Images

Icon: Mousavi may lose, but his movement will endure.

Mahmoud Ahmadinejad's official electoral victory in Iran continues to pit the baton against the green flag in a battle between state security forces and an army of Mir Hossein Mousavi supporters, armed with nothing but unity and a limited degree of strength in their numbers.

Amid the protests, the international community, most notably the United States, Britain, and the European Union, is either -- depending on your viewpoint -- taking a cautious stance or dithering over what to do. The dilemma for Western officials is this: Do they build on the democratic movement unfolding in Iran and assist with the uprising or a coup d'état, or do they bide their time, take a step back, and reconcile themselves to an Ahmadinejad-led Iran?

Serious events are unfolding in Tehran that make it tempting for foreign forces to capitalize on the moment and try to promote change, without necessarily resorting to armed conflict -- simply take out Mahmoud Ahmadinejad's name, put in Shah Mohammed Reza Pahlavi, and you have 1978 Iran with the same fear, despair, and furious protests against dictatorship and tyranny.

What makes this discontent dangerous for the Islamic regime is that the widespread unrest, the biggest since 1979, is led not by some opposition group in exile or as part of some foreign-sponsored "color revolution," but by domestic forces operating under the leadership of former post-Iranian Revolution Prime Minister Mir Hossein Mousavi, who has the backing of fellow presidential candidate Mehdi Karroubi, a collection of senior Islamic clerics, and powerful former President Akbar Hashemi Rafsanjani. The regime's reaction in the form of mass censorship, widespread arrests, and unleashing of security forces upon the population in a ruthless and systematic manner shows a government struck down with fear and worry, giving the lie to the calm and collected posture of Ahmadinejad in his numerous post-election appearances. For the first time, the very legitimacy of the Islamic Republic is being questioned not just abroad, but also at home.

So why is the international community yet to seize on this opportunity? One reason could be that Western leaders think that any so-called "green revolution" would make no difference in the foreign-policy challenges that Iran, in its current shape and form, presents them, and as a result are reluctant to back a losing horse.

There's something to this argument. Even with Mousavi in power, Iran's foreign policy would likely be no different than it has been under Ahmadinejad. A 20-year absence from the public eye, coupled with dazzling words of change that skillfully capitalize on the "Obama effect" gripping the world, does wonders to beguile a young generation of supporters who never knew or have forgotten the radicalism and bloodshed that marked Mousavi's tenure as prime minister from 1981 to 1989 (the Iranian Revolution's most significant years).

Indeed, anyone believing Mousavi would be the one to unclench the Iranian fist for a hand-in-hand partnership of peace with the United States is guilty of wishful thinking. It was Mousavi, after all, who was at the center of the Iran hostage crisis and remains complicit in an operation he commended as "the beginning of the second stage of our revolution." And it was Mousavi who was the protégé of Ayatollah Ruhollah Khomeini (chief architect of the Iranian Revolution and founder of theocratic Iran), a former member of Hezbollah's leadership council, sworn enemy of Israel, and a prime minister under whose watch thousands of political prisoners were massacred in 1988. And finally, it was Mousavi who initiated Iran's nuclear program in the 1980s and likely would be intent on carrying through Iran's nuclear ambitions, the foremost issue central to any improvement in relations with the West.

All of this discussion assumes that it is even worth debating whether Mousavi would bring change to Iranian foreign policy when he would have no authority to do so in the first place. Supreme Leader Ayatollah Ali Khamenei has the final say on matters of foreign policy, not the president. Given Khamenei's clear approval of what he called a "glittering" Ahmadinejad victory, and because it is the theocracy that verifies the count in the absence of any outside monitors -- meaning that any election rigging was done with the supreme leader's backing -- it is he who will need convincing if Iran is to divert from a path of nuclear capability, hostility toward the United States, and support for terrorism.

Still, these assumptions -- widely held in the international community -- are now open to question. Although a Mousavi presidency itself would probably not deliver a sensational change in Iranian foreign policy, the movement he has spawned might. The tenacious middle-class, educated, and youthful Mousavi supporters who have cried foul and rallied and bled in the streets could bring a new order to Tehran by forcing the country's supreme leader to take into account public opinion that demands engagement with the West.

More likely, however, the unelected mullahs who rule Iran behind the scenes will be concerned about a galvanized army of reformists who have undermined its authority in recent weeks by, for example, entering the squares and openly mixing and dancing in groups of males and females in direct contravention of clerical law. The leadership might therefore double down on its hard-line foreign and domestic policies, starting with a ruthless endeavor to keep Ahmadinejad in power through any means necessary, so long as the end remains a theocratic Iran.

Whoever wins this violent showdown, there is one clear loser -- the Islamic Republic, whose internal legitimacy has forever been shattered. Should Mousavi go down fighting, that's one victory that can never be taken away from his brave supporters.