Dina Esfandiary is an Iran specialist and a Research Associate in the Non-proliferation and Disarmament programme at the International Institute for Strategic Studies.

Next Friday Iran will hold its presidential election. Since 21 May, eight pre-approved candidates have been battling it out to prove to Iranians they're most suited to lead them. But the opinion of only one Iranian really matters: Supreme Leader Ayatollah Khamenei. And it seems he's already made his decision.

Politics in the Islamic Republic is neither unified nor monolithic. It is dynamic, with a range of views represented in the political system.

But all these views are ultimately overseen by the Supreme leader, the final decision-maker. And Khamenei was left a little shaken by the events that followed the contested 2009 elections. To add insult to injury, the candidate who most benefited from his support last time, President Mahmoud Ahmadinejad, thanked him by subsequently making the Supreme leader's life difficult.

Ahmadinejad fell out with Khamenei and much of the Iranian establishment during his second term, sparking another round of political wrangling and forcing Khamenei to step in multiple times and call for restraint.

Many hoped these elections would help overcome the system's damaged credibility. And for a moment, this seemed possible. The registrations of Akbar Hashemi Rafsanjani, the popular former president, and Rahim Mashaei, Ahmadinejad's protégée, as presidential candidates just in the nick of time surprised Iran watchers everywhere. But on the 21 May, when Iran's powerful Guardian Council announced the final list of candidates, shortened from the more than 650 registered potentials, both men were disqualified. It became clear that this year Khamenei wasn't going to take any chances.

So eight lacklustre candidates remain, all loyal to Khamenei. Or so he thought.

Hassan Rowhani, a cleric and former nuclear negotiator, has emerged as a surprise reformist candidate. Although he always had the reputation of a pragmatist, his recent criticisms of government policy in all sectors, as well as calls for the right to privacy to be respected and equal opportunities for women, have raised eyebrows within the regime. Predictably, they also led to some of his staff being harassed this week.

What does this surprising development mean? Rowhani's candidature and campaign is drawing a lot of attention from Iranians surprised at his blunt and uncompromising attitude in interviews and debates. They are listening with interest to his plans to address problems such as unemployment, inflation and government interference in the daily lives of Iranians. At the same time, he is defending his credentials as a supporter of the revolution and resistance to the West.

But this inevitably means that he stands little chance of winning. Similar to popular Tehran Mayor Mohammad Bagher Ghalibaf, Rowhani is considered a bit of a loose cannon by the Iranian establishment.

Iran's elections are notorious for their surprises, making the outcome difficult to predict. But with the disqualification of Rafsanjani, Khamenei signaled that this year, he would take no risks. The next Iranian president will likely be someone he can control, whose loyalty is unflinching.

Khamenei's chosen man seems to be current nuclear negotiator Saeed Jalili (pictured). Relatively unknown within Iran until now, Jalili lacks experience in national politics. From the regime's perspective, he compensates by being a staunch conservative. Despite the Iranian population's focus on domestic problems, Jalili has used the country's nuclear program as a platform for his election bid. He claims that under his watch Iran has '(stood) up to the oppressive powers' while they have 'surrendered' in the face of resistance.

A Jalili win would frustrate the P5+1 negotiations over Iran's nuclear program because it would indicate Khamenei's unwillingness to change course on the nuclear file. Jalili is not just any conservative candidate; he specifically opposes the West's primary objective in the region: curbing Iran's nuclear ambitions. By choosing him, Khamenei ensures a more unified front will face the P5+1.

Indeed, with Jalili as Iran's president, US President Obama's claim that 'all options are on the table' with respect to the nuclear issue will be tested more than ever.