... For some, the greatest value in an agreement lies in the prospect of an end, or at least a moderation, of Iran’s 3½ decades of militant hostility to the West and established international institutions, and an opportunity to draw Iran into an effort to stabilize the Middle East. Having both served in government during a period of American-Iranian strategic alignment and experienced its benefits for both countries as well as the Middle East, we would greatly welcome such an outcome. Iran is a significant national state with a historic culture, a fierce national identity, and a relatively youthful, educated population; its re-emergence as a partner would be a consequential event. 

But partnership in what task? Cooperation is not an exercise in good feeling; it presupposes congruent definitions of stability. There exists no current evidence that Iran and the U.S. are remotely near such an understanding. Even while combating common enemies, such as ISIS, Iran has declined to embrace common objectives. Iran’s representatives (including its Supreme Leader) continue to profess a revolutionary anti-Western concept of international order; domestically, some senior Iranians describe nuclear negotiations as a form of jihad by other means.

The final stages of the nuclear talks have coincided with Iran’s intensified efforts to expand and entrench its power in neighboring states. Iranian or Iranian client forces are now the pre-eminent military or political element in multiple Arab countries, operating beyond the control of national authorities. With the recent addition of Yemen as a battlefield, Tehran occupies positions along all of the Middle East’s strategic waterways and encircles archrival Saudi Arabia, an American ally. Unless political restraint is linked to nuclear restraint, an agreement freeing Iran from sanctions risks empowering Iran’s hegemonic efforts.

Some have argued that these concerns are secondary, since the nuclear deal is a way station toward the eventual domestic transformation of Iran. But what gives us the confidence that we will prove more astute at predicting Iran’s domestic course than Vietnam’s, Afghanistan’s, Iraq’s, Syria’s, Egypt’s or Libya’s?

Absent the linkage between nuclear and political restraint, America’s traditional allies will conclude that the U.S. has traded temporary nuclear cooperation for acquiescence to Iranian hegemony. They will increasingly look to create their own nuclear balances and, if necessary, call in other powers to sustain their integrity. Does America still hope to arrest the region’s trends toward sectarian upheaval, state collapse and the disequilibrium of power tilting toward Tehran, or do we now accept this as an irremediable aspect of the regional balance? ...