An Iranian woman holds a poster of Iranian Supreme Leader Ayatollah Ali Khamenei, and late revolutionary founder Ayatollah Khomeini, during an anti-Saudi protest rally in Tehran in 2015. (Vahid Salemi/Associated Press)

Ray Takeyh is a senior fellow at the Council on Foreign Relations and the co-author of “The Pragmatic Superpower: Winning the Cold War in the Middle East.”

It is often suggested that the most consequential barrier to Iranian pragmatism is Supreme Leader Ayatollah Ali Khamenei. Once the elderly Khamenei passes from the scene, the argument goes, his successors will embrace prevailing international norms. The sunsetting restrictions of the nuclear deal need not be of concern, for a revamped Islamist regime will find global integration too tempting to discard for the sake of nuclear arms. The only problem with such expectations is that the candidate Khamenei and the Revolutionary Guards are grooming to ascend to the post of supreme leader is one of the most reactionary members of Iran’s ruling elite. Ibrahim Raisi, Iran’s probable next supreme leader, could be the only person in the Islamic Republic who could cause people to miss Khamenei.

Raisi is 56 years old and, like Khamenei, hails from the city of Mashhad. After a stint in the seminary, he has spent his entire career in the Islamic Republic’s enforcement arm, serving as prosecutor general, head of the General Inspection Office and lead prosecutor of the Special Court of the Clergy, which is responsible for disciplining mullahs who stray from the official line. In one of his most notorious acts, he served as a member of the “Death Commission” that, in the summer of 1988, oversaw the massacre of thousands of political prisoners on trumped-up charges.

The position of the supreme leader was once thought to belong to an esteemed cleric known for his theological erudition. However, Khamenei’s lackluster religious credentials have paved the way for an even less impressive figure who has spent his professional life weaving conspiracies in the regime’s darkest corners.

Raisi’s background fits nicely with the Revolutionary Guards’ mission of crushing dissent. In a recent interview, Revolutionary Guards commander Muhammad Jaffari conceded that since 2005, the regime has come to see domestic insurrection as an even greater challenge to its existence than external pressures. The ideal successor to Khamenei would have to not only share the Guards’ perspective but also have close ties to the security organs and the judiciary. The Guards seem to have found their man. Raisi is being increasingly touted by them as a vanguard of the regime and an enforcer of its will.

Khamenei is an even more consequential backer. Iran’s supreme leader recently appointed Raisi to head one of Iran’s largest charitable foundations, Astan Quds Razavi. The foundation manages the Imam Reza Shrine in Mashhad, which is visited by millions of pilgrims each year, operates many other enterprises and has vast land holdings. Though difficult to estimate with precision, the endowment’s value is reported to be upward of $15 billion. This appointment not only enhances Raisi’s national profile but also puts at his disposal enormous funds that he can use to nurture his own network of supporters and constituents. Khamenei, in essence, has opened the gates of the Islamic Republic’s murky financial universe to Raisi.

For Khamenei and his praetorian guards, the most important question is not just the survival of the regime but also its revolutionary values. They are determined that Iran will not become another China, which they see as having relinquished its ideological inheritance for the sake of commerce. The 2009 uprising may be a faded memory in Washington, but it was a watershed event for the guardians of the theocracy. Under Khamenei’s watchful eye, Iran is being transformed into a police state. The logical extension of these developments is a supreme leader who comes from the heart of Iran’s repressive organs.

Iran’s formal procedures would suggest that the Assembly of Experts will choose the next leader, but in reality that decision is being made right now in the state’s backrooms. President Hassan Rouhani may be a subject of U.S. fascination and hopes of a moderate regime, but he is a bystander in this important power play. Khamenei and the Guards appreciate that the next supreme leader will assume power in a precarious time. This leader has to share their penchant for conspiracy theories, demonstrate a contempt for the West and be prepared to shed blood on behalf of the regime. The next supreme leader has to not only believe in the theocracy’s mission of repression but also have been an integral part of that machinery.

No one in the Islamic Republic embodies these attributes more than Raisi. He seems to be the right man for the right time.