The Islamic Republic today is garnering attention primarily for its nuclear defiance. However, beneath the glare of inconclusive summits and boisterous claims of economic empowerment, a critical question remains: Just how stable is Iran’s clerical regime?

For much of the Washington establishment, the opposition Green movement is a faded memory, a protest wave against electoral fraud that was suppressed by the Islamist regime to the point of exhaustion if not extinction. Such sentiments fail to engage with a more fundamental question, namely how to assess the viability of an opposition movement in a country whose politics have proven so evasive.

The Islamic Republic is not a typical authoritarian state but a distinct ideological construct. Such regimes require an explanation, an argument to justify their repression and meddlesome adventures abroad. The custodians of the theocratic state may engage in atrocities, but they are doing so to advance history’s cause, to realize a certain sublime ideal. In such a state, the uniformed officer, the plainclothes policeman, the Revolutionary Guard all require an overweening ideological cover to justify their brutalities to themselves.

The subtle and subversive victory of the Green movement is to hollow out the state and demonstrate to its loyalists that they are not defending a transcendent orthodoxy but craven and cruel men addicted to power at all cost. In the words of the reformist cleric, the late Ayatollah Hossein Montazeri, in the violent crackdown following the elections in June 2009, the Islamic Republic ceased to be either Islamic or a republic.

In his seminal study of revolutions, Crane Brinton observed that a ruling class becomes imperiled when “numerous and influential members of such a class begin to believe that they hold power unjustly, [and] that the beliefs they were brought up on are silly.”

Since Iran’s fraudulent presidential election, a steady stream of the regime’s elite are relinquishing their revolutionary inheritance and separating themselves from a government they once defended. The first generation of revolutionaries who were present at the creation of the republic, former presidents, members of Parliament and stalwarts of the state have abandoned the presumptions of their militant brethren. The shrinking leadership of the Islamic Republic is increasingly finding itself in the same place as the masters of the Soviet Union, resting its power on a seemingly impressive edifice of terror that is likely to prove just as unreliable and unsteady.

Along with defections among the elite, the Islamic Republic continues to confront popular resistance. The principal objective of any dictatorship is to atomize its society, keeping individuals locked — alone and dispirited — in its system of oppression. However, the Greens have proved that in the 21th century, technology has done much to erode such absolutist pretensions. Social media networks have fostered communities that defy the mullahs’ superstructure and provoke acts of protest. Iran is a land of work stoppages, student demonstrations and sporadic commemoration of symbolic events. The persistence of dissent is having a corrosive impact on a regime that finds itself confronting a crisis of legitimacy it cannot redress and acts of defiance that it cannot extinguish.

The achievements of the Green movement are impressive: It has fractured the state, won the intellectual argument regarding the future of Iran, and attracted a large segment of the public. But it is important to stress that there is no guarantee that the Greens will succeed the theocratic autocrats. Although the Islamic Republic is heading relentlessly yet uneasily to history’s junkyard, the future of Iran is still a subject of contention and struggle. In its post-Islamic Republic phase, Iran may degenerate into a period of prolonged violence and even ethnic separatism. A new dictatorship could arise, basing its power on Persian chauvinism rather than Islamist assertion. The series of decisions that the United States and its allies make today will help condition the contours of power in tomorrow’s Iran.

This is not to suggest that the United States should cease negotiating with Iran. Ronald Reagan continued to sign arms control compacts with a Soviet Union whose demise he perceived as certain. The pursuit of important security objectives did not derail Reagan from embracing Solidarity in Poland or comparable opposition groups throughout Eastern Europe. The important point is that the Iran conundrum is not limited to compelling Tehran to spew out some of its accumulated uranium. Our choices speak as much to our values as they do to our interests. In the long run, America has never gone astray by standing with those who hope for a more decent future.

Ray Takeyh is a senior fellow at the Council on Foreign Relations.