DUBAI, United Arab Emirates >> Iranians vote today for the next president of the Islamic Republic, but how does that elected leader fit into the country’s clerically managed government that approves candidates ultimately overseen by its supreme leader?

THE SUPREME LEADER’S POWER

At the heart of Iran’s complex power-sharing government created after its 1979 Islamic Revolution is the supreme leader, a position now held by Ayatollah Ali Khamenei. The supreme leader also serves as the country’s commander in chief over its military and the powerful Revolutionary Guard, a paramilitary force involved in the war in Syria and the battle against the Islamic State group militants in Iraq that also has vast economic holdings across Iran. An 88-member elected clerical panel called the Assembly of Experts appoints the supreme leader and can remove one as well, though that’s never happened.

THE PRESIDENT’S POWERS

Iranian presidents serve four-year terms. Iran’s president is subordinate to the supreme leader but still powerful with considerable influence over both domestic policy and foreign affairs. In Rouhani’s case, his administration negotiated the 2015 nuclear deal with world powers, which saw Iran limit its enrichment of uranium in exchange for the lifting of economic sanctions. That accord was done with Khamenei’s blessing.

NARROWING THE FIELD OF CANDIDATES

An initial field of over 1,600 hopefuls registered to run in the election. Iran’s Guardian Council, a 12-member panel half selected by the supreme leader and half nominated by the judiciary and approved by parliament, vetted the candidates and narrowed the field to six, including Rouhani. The council has never allowed a woman to run for president and routinely rejects candidates calling for dramatic reform, stifling change while ensuring the continuation of Iran’s Shiite Islamic governance. Of the six candidates approved, two have since dropped out.

ROUHANI’S CAMPAIGN

Rouhani, a cleric, says his moderate administration needs to continue its work to implement the nuclear deal. In campaign stops and debates, he’s struck an increasingly more-forceful line against the Revolutionary Guard and hard-liners for ballistic missile launches and arbitrary arrests, something he largely avoided doing so far in his time in office. Rouhani remains the favorite of analysts as every Iranian president since Khamenei himself took the presidency in 1981 has won re-election. However, Iran’s sluggish economy and poverty remain the top issues for average Iranians who have yet to see the benefits of the atomic accord.

ROUHANI’S MAIN OPPONENT

Hard-line cleric and former judge Ebrahim Raisi appears to be Rouhani’s main challenger. Raisi is perceived to be close to Khamenei as the supreme leader put him in charge of Astan Quds Razavi, a vast charitable foundation encompassing businesses and endowments that oversees the holy Shiite shrine of Imam Reza in Mashhad. He also has received the endorsement of two major clerical organizations that declined to endorse Rouhani in his 2013 campaign. Raisi has said he won’t seek to tear up the nuclear deal. Raisi also has offered populist promises, including monthly cash payments to Iran’s poor. However, his candidacy has revived the controversy surrounding the 1988 mass execution of thousands in Iran. Raisi allegedly served on a panel involved in sentencing the prisoners to death.

WHAT SUBJECT LARGELY HASN’T BEEN DISCUSSED IN THE RACE?

Surprisingly, Islam. “Candidates have seemingly concluded that Islamic ideology has lost its power as a driving factor among voters and is therefore not worth addressing,” wrote Mehdi Khalaji, an analyst at the Washington Institute for Near East Policy who is Shiite theologian by training.

HOW IRANIANS VOTE

Any Iranian 18 or older can vote in today’s election. To cast a ballot, they must go to one of 63,500 polling centers set up around the country in mosques, schools and other public buildings. A voter must show their national ID card and fill out a form. They dip one of their index fingers in ink, making a print on the form, while officials stamp their ID so they can’t vote twice. The voter then writes down the name and the numerical code of the candidate they want to elect on the secret ballot and drop it into a ballot box. Voting lasts from 8 a.m. until 6 p.m., though authorities routinely keep polls open at least several hours later.

A LOOK AT ELECTION OVERSIGHT

Iranian elections are run by the country’s Interior Ministry, which oversees the nation’s police forces. The Guardian Council must sign off any final election results. Iran bars domestic and international observers from the elections, bucking a widely accepted principle around the world that international watchdogs warn can allow for fraud. Allegations of voter fraud marred the country’s 2009 election, which saw hard-line President Mahmoud Ahmadinejad secure a second term amid widespread unrest. The Guardian Council rejected Ahmadinejad’s bid to run again in today’s election, likely to avoid any similar conflict.

SO IS IRAN A DEMOCRACY?

Iran describes itself as an Islamic Republic. It holds elections and has elected representatives passing laws and governing on behalf of its people. However, the supreme leader has the final say on all state matters and the Guardian Council must approve all laws passed by the parliament. Those who led Iran’s Green Movement after Ahmadinejad’s disputed 2009 re-election remain under house arrest. Security forces answering only to the supreme leader also routinely arrest dual nationals and foreigners, using them as pawns in international negotiations.