Ahmad Vahidi, commander in chief of Iran’s Islamic Revolutionary Guard Corps, advocated striking Israel hard to stop attacks on Hezbollah in Beirut, according to Iranian and Arab officials. More moderate voices in the Iranian leadership wanted to hold off on the strikes, the officials said, for fear of jeopardizing a deal with the U.S. that could save Iran’s economy. Vahidi won the argument, persuading Iran’s top security council to back the strikes and setting off the first exchanges of fire between Iran and Israel since a ceasefire on April 8.

Vahidi has emerged as a key power broker pushing a hard line at the negotiating table with Washington. President Trump and mediators signaled Saturday that they were on the cusp of a preliminary deal with Tehran, with a signing possible as soon as Sunday, according to the Wall Street Journal. But Iran pushed back on the timing. In Iran, the Revolutionary Guard and those close to it have stood as the biggest obstacle to an agreement, mediators said.

Vahidi insists that Iran must re-establish military deterrence to increase its leverage at the negotiating table, mediators said. He has pushed negotiators to protect Iran’s missile stockpile and gain access to its frozen funds, and has argued that those funds should not be barred from military spending. His forces are in charge of imposing Iran’s stranglehold on the Strait of Hormuz, the regime’s strongest card in negotiations.

Throughout the war, Vahidi has frequently overruled Foreign Minister Abbas Araghchi and President Masoud Pezeshkian, said Arab, Iranian and European officials. Both have pushed for a swift, preliminary deal with the U.S. to avoid an economic implosion under pressure from the U.S. blockade of Iran’s oil industry. Vahidi, by contrast, has given priority to re-establishing Iran’s deterrence and defending Hezbollah, the Lebanese militant group backed by Tehran. It was Vahidi who hitched the fighting in Lebanon to the war in Iran, making a deal with the U.S. dependent on Israel’s ending its conflict with Hezbollah, according to Arab mediators.

Vahidi, 67, was a founding member of the Revolutionary Guard after the Islamic revolution in 1979, and took charge of its intelligence branch in 1982 at age 23, according to the Wall Street Journal. He helped establish the Quds Force, an elite unit of the Revolutionary Guard that specialized in training foreign militias to attack Iran’s enemies, and rose to become its first commander in 1988. As head of that force in the 1990s, he helped develop Hezbollah into the dominant military force in Lebanon.

Argentina, through Interpol, issued an arrest warrant for Vahidi in 2007, accusing him of helping orchestrate the 1994 bombing of a Jewish community center in Buenos Aires that killed 85 people and injured hundreds more, the Wall Street Journal reported. The Islamic Republic has repeatedly denied that Vahidi or any other Iranian official was involved in the attack.

He has served in a range of roles that gave him deep knowledge of Iran’s defense and security apparatus, including defense minister, interior minister and a deputy commander in the Revolutionary Guard. As defense minister in 2009, he played a key role in procurement for Iran’s missile, drone and nuclear programs, according to the U.S. Treasury, which placed sanctions on him in 2010. As interior minister in 2022, he oversaw the deadly crackdown on protests over the death of Mahsa Amini, the 22-year-old woman killed in police custody after allegedly violating the country’s strict Islamic dress codes.

Despite his clout in Tehran, Vahidi now holds a perilous crown, the Wall Street Journal reported. U.S. and Israeli airstrikes have killed a string of Revolutionary Guard commanders, including his predecessor and General Qassem Soleimani, the former commander of the Quds Force killed in a strike ordered by Trump in his first term. An early example of his assertiveness came when President Pezeshkian said Tehran would halt its strikes against Gulf neighbors, and the Revolutionary Guard swiftly contradicted him. On April 18, when Iran’s top diplomat Araghchi said the Strait of Hormuz was open, the Revolutionary Guard told mediators otherwise, Arab officials said.

Going deeper: Read MSI’s analysis of Iran’s IRGC overriding civilian negotiators →