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

On the surface, the Islamic Republic of Iran is an unsavory authoritarian state unworthy of support, much less acclaim. A regime that is deeply embedded in Syria’s civil war and has embraced terrorism as an instrument of statecraft would seemingly be at a disadvantage in presenting its case to the international community. Yet Iran has had some success imposing its narrative on the negotiations Iranian officials and Western nations are conducting about its nuclear program. The theocratic state demands that its “right to enrich” be recognized upfront and that its past nuclear infractions be forgiven. The great powers’ diplomacy will be judged not by clever formulations they devise to accommodate Iran’s “red lines” but by their ability to veer Tehran away from its maximalist positions.

President Hassan Rouhani has managed to inculcate the notion that he is under pressure from hard-liners at home and that a failure by the great powers to invest in his presidency would end Iran’s moderate interlude. The implication: Time is of the essence, and the West should not miss an opportunity to deal with pragmatists who seek a breakthrough on Iranian arms control.

But a more careful examination reveals that the Islamic Republic has reached an internal consensus. It is ruled today by a national unity government. The factionalism that has historically bedeviled the theocracy has, for now, been set aside.

For Iran’s supreme leader, Ayatollah Ali Khamenei, the most important objective is the survival of the regime and preservation of its ideological character. As an astute student of history, Khamenei senses that disunity among the elites can feed popular discontent and imperil the regime. The fraudulent presidential election of 2009 caused not only a legitimacy crisis but also a fracture among the regime’s elite. By conceding to Rouhani’s election, Khamenei has managed to restore a measure of accountability to the system and has drawn some of his disgruntled cadre back to the fold. Given such domestic calculations, Rouhani’s political fortunes are not necessarily contingent on the success of his arms-control policy. Khamenei clearly hopes that his president can ease Iran’s economic distress, but the notion that Rouhani will be displaced unless he can quickly obtain concessions from the West is spurious.

If their diplomatic efforts are to succeed, Western powers would be wise to reject the nuclear alarmism that often surrounds this issue. The standard U.S. government assessment is that Iran is still a year away from getting the bomb. This year includes the time required to enrich uranium to weapons-grade and to assemble a nuclear device. But this timeline requires Iran to divert material from safeguarded facilities, an action that would quickly be detected by the International Atomic Energy Agency and that probably would provoke an international reaction. Accordingly, there is nothing magical about 2014. Time is on the side of the United States, not Iran — where economic conditions are worsening by the day.

Another issue that has paradoxically redounded to U.S. advantage was Rouhani’s trip to the U.N. General Assembly. Both U.S. and Iranian officials unwisely raised expectations in September and fed a media narrative of an imminent historic breakthrough between two old nemeses. Such raised expectations work to the disadvantage of Iran rather than the United States. Suddenly, the hard-pressed Iranian public has come to expect imminent financial relief. Should the negotiations not yield an accord in a timely manner, it is Khamenei, not President Obama, who would face a popular backlash. A disenfranchised and dispossessed population is an explosive political problem for Khamenei. The Western powers should not be afraid to suspend negotiations or walk away, should the Iranians prove intransigent. Ironically, stalemated negotiations are likely to pressure Iran into offering more concessions.

During the past decade, two U.S. administrations have confounded their critics by crafting a formidable sanctions architecture and adroitly managing an unruly alliance system. It is important to have a proper estimation of the Islamic Republic — a second-rate power with a third-rate nuclear program. Khamenei presides over a government that is despised by its constituents and distrusted by its neighbors. U.S. sanctions policy has offered its diplomats indispensable leverage. Washington is in a position to demand the most stringent of nuclear accords and should pay scant attention to Iran’s oft-proclaimed red lines. An agreement that not only buys time but also prevents Iran from permanently reconstituting its nuclear weapons ambitions is within grasp. With patience and firmness, a great diplomatic victory can still be claimed.