Iranian President Hassan Rouhani at the Saadabad Palace in Tehran on Feb. 11. (Ebrahim Noroozi/Associated Press)

Iran’s official month-long presidential campaign period kicked off last week in the run-up to the May 19 election. While former president Mahmoud Ahmadinejad’s candidacy garnered international headlines, the real major development came when Ebrahim Raisi — touted as a potential successor to Iran’s aging supreme leader — entered the race.

Instead of a straightforward reelection campaign for Iran’s incumbent president, the question of supreme leader succession now looms over next month’s election.

Rouhani has a mixed record during his first term as president. He negotiated the Joint Comprehensive Plan of Action (JCPOA) with the P5+1 (China, France, Germany, Russia, the United Kingdom and the United States plus the European Union), lifting international sanctions imposed over the Iranian nuclear program. Rouhani also introduced better economic management, which, alongside the sanctions relief of the JCPOA, generated a modest economic recovery after the Ahmadinejad years. Rouhani continues to be backed by a super-coalition of Iranian political currents composed of reformists, centrists and even moderate conservatives.

But his first term did not fulfill the lofty rhetoric of his campaign. In a recent national opinion poll of a representative sample of Iranians, a majority of those surveyed thought Rouhani has not been successful in resolving the country’s economic problems and are pessimistic about future prospects. Rouhani has also not been able to fully deliver on his campaign promises of expanding social and political freedoms. Just over half of respondents said they think it is likely that Rouhani may lose the upcoming election — even though they also viewed him as the candidate most able to accomplish goals on issues including foreign relations, civil liberties and the economy.

The poll indicates that Iranians overwhelmingly view economic issues as the most pressing. Rouhani’s liberal economics will be challenged by conservative populism. Foreign policy and national security may also gain in importance as tensions with the United States under President Trump continue to rise, and hawkish Iranian conservatives seek to discredit the JCPOA, arguing that Iran conceded too much for far too little in return.

Two of Rouhani’s challengers bear watching. Raisi — a potential successor to the supreme leader — is a mid-ranking Shiite cleric who dons a black turban — denoting that he is a descendant of the prophet Muhammad — a symbol that appeals to many devout Iranian voters. He began his career as a young judiciary official after the Iranian Revolution and — according to a recording of the late Grand Ayatollah Hossein Ali Montazeri (leaked in August) — was involved with the mass execution of political prisoners in summer 1988. Raisi climbed the judicial ladder, a path to power for clerics in Iran more interested in government service than seminary life, to become deputy chief justice and attorney general.

In the past year, some conservatives began to portray Raisi as a candidate to succeed Ayatollah Ali Khamenei. In March 2016, Raisi was appointed chairman of the Astan Ghods Razavi, an organization that ostensibly manages the Imam Reza shrine and acts as a charitable foundation. In reality, the Astan is a multibillion-dollar conglomerate and semiautonomous political fiefdom that exerts enormous influence in Mashhad, the second-largest city in Iran.

Raisi was also chosen as the top candidate for the leading conservative political organization, the Popular Front of the Islamic Revolution Forces, despite being a virtual unknown in electoral politics until the current presidential election cycle.

Iranian conservatives, referred to as “principlists” in Iran, have not performed well in national elections in the last four years. The Popular Front is an attempt by conservatives to remedy their poor performance in previous elections by better organizing through grass-roots efforts and creating consensus around a single presidential candidate to avoid vote splitting. While Raisi has acknowledged their support, he has not joined their ranks.

One rationale behind Raisi’s sudden entry into the election may be to help unite conservatives. Winning the presidency may in turn be seen by him and his allies as a springboard to the supreme leadership, and simultaneously as a way to spoil Rouhani’s own prospects. But a poor performance could just as easily kill Raisi’s chances.

The second candidate to watch is Mohammad Bagher Ghalibaf, the mayor of Tehran and the Popular Front’s second candidate. A perennial presidential candidate who came in a distant second behind Rouhani in the 2013 election, Ghalibaf is expected to campaign but drop out of the election before the May 19 vote in favor of Raisi.

However, the Iranians surveyed in the national opinion poll viewed Ghalibaf most favorably of all of the candidates, whereas nearly half could not even identify Raisi. If late into the campaign Ghalibaf remains the most popular conservative candidate, he may simply refuse to drop out.

The prospect of Raisi’s candidacy for supreme leader may itself become a campaign issue and source of popular mobilization in favor of Rouhani. Some voters may relish the idea of defeating a possible future conservative supreme leader at the ballot box, especially one associated with one of the most tragic events in the history of the Islamic Republic.

Beyond popular unease with what his presidency would mean for civil liberties, the untested Raisi will have an uphill struggle to convince Iranian voters that he is best suited to lead the country amid a fragile economic recovery and fraught foreign relations.

How these complex dynamics play out in the campaign remains fluid. This election, as it stands, defies easy prediction, both of its immediate outcome and ultimate consequences.

Farzan Sabet is a Stanton Nuclear Security Fellow at the Center for International Security and Cooperation, Stanford University, and a PhD candidate in international history at the Graduate Institute, Geneva. Follow him on Twitter @IranWonk.