The same hawks in western capitals who welcomed the US’s assassination this month of Qassem Suleimani will also have felt vindicated by the elevation of his deputy the following day to lead the Islamic Revolutionary Guard Corps Quds Force, which is responsible for covert operations outside Iran.

Leaving to one side the law of unintended consequences, that vindication will have been based not just on the fact that an unusually dangerous and well-connected player had been removed from the Middle Eastern tinderbox, but, better still, that his successor, Esmail Qaani, was a known quantity.

Those familiar with the region’s clandestine lore may have recalled, however, that when Suleimani himself was appointed to that post in 1997 – plucked from operations on the border with Taliban-controlled Afghanistan – there was some scepticism that he could match the man he replaced.

That man was Ahmad Vahidi, believed to have overseen Hizbullah’s bombing of the Israeli embassy in the Argentinian capital Buenos Aires in March 1992, which killed 29 people, and an attack on a Jewish cultural centre in the same city two years later that added 85 more to the death toll.

Iran regarded those attacks as successes almost without precedent against Israel. Vahidi went on become defence minister under President Mahmoud Ahmadinejad. He’s now a member of the elite Expediency Council, chosen personally as advisers by the supreme leader every five years.

Charisma

Yet when replacing Vahidi, Suleimani emerged as a new leader of considerable charisma. His success was built not alone on his skill as a military strategist and ubiquitous militant networker, but on the fact that his charisma allowed him to develop a direct channel to supreme leader Ali Khamenei – building a well-justified reputation as the second most powerful person in Iran.

So who is Esmail Qaani, and where does this position him?

The most important calculation being made by those same western hawks will undoubtedly be that Qaani, a veteran of the Iran-Iraq war, does not have that same unmediated access to the supreme leader and therefore cannot bypass the formal chain of command.

That will be balanced against the fact that Qaani was Suleimani’s deputy from the start. He learned at the knee of a unique superior famously described by one US analyst as the equivalent of Iran’s special forces commander, its CIA director and its foreign minister all rolled into one.

It was Qaani – whose key responsibility under Suleimani was areas east of Iran – who conceived and executed the highly successful tactical plan to recruit Afghan and Pakistani Shia fighters to fight for President Bashar al-Assad in Syria.

Having watched Suleimani network with Hizbullah, with Houthi groups in Yemen, Palestinian militants, and paramilitary groups in Iraq, Qaani is intimately familiar with Iranian financial support for this underworld over the years, the weapons it has funded and the attacks it has underwritten.

More than that – as Daniel Byman of Georgetown University points out – Qaani comes from an Iranian tradition of “rewarding aggressive officers, suggesting Suleimani’s successors may also be eager for confrontation”.

Retaliation

In the medium term Qaani has already made clear his agenda in retaliation for Suleimani’s death: to drive US forces out of the Middle East.

Nowhere is Iran closer to achieving a substantial jumping-off point for that goal than in Iraq, where its Shia militia proxies – such as the Khazali brothers – have been ratcheting up political pressure on an ever-weaker government in Baghdad.

If he were to achieve only that, a complete US withdrawal from Iraq, Qaani – even at 62 a man with a reputation to consolidate and burnish – would have assured his place in the Revolutionary Guard pantheon.

The devastating twin effects would be to effectively transfer control of Iraq from Washington to Tehran, and to ensure a resurgence of Islamic State, transforming the strategic map of a large swathe of the Middle East and unleashing a chain of those unintended consequences.