The unthinkable has happened. Gen. Qasem Soleimani, the man behind Iran’s drive for regional hegemony, who commanded the Quds Force of the Islamic Revolutionary Guard Corps, was targeted and eliminated. Unlike all the previous times when he got away, this time, he met his end.It appears a cryptic tweet from US Defense Secretary Mark Esper announced the US policy to begin preemptive strikes against Iranian adversaries or their proxies. “To Iran and its proxy militias: We will not accept the continued attacks against our personnel and forces in the region. Attacks against us will be met with responses in the time, manner and place of our choosing. We urge the Iranian regime to end malign activities,” he wrote. It is not known whether the US acted alone – or if not, who else may be responsible for the precision air strike. Secretary of State Mike Pompeo had called Middle East leaders in the last days to firm up support and discuss strategy. Prime Minister Benjamin Netanyahu, UAE Crown Prince Mohammed bin Zayed Al Nahyan and Crown Prince Mohammed Bin Salman in Saudi Arabia were all contacted by him, as were Iraqi leaders and Qatar.He warned Soleimani’s key disciple Abu Mahdi al-Muhandis as well as Qais al-Khazali, a Shi’ite militia leader the US had sanctioned; then he warned the leaders of the Iranian-backed Popular Mobilization Units, Hadi al-Amiri and Faleh al-Fayed.Muhandis was responsible for the December 27 attack on US forces at K-1 which resulted in the death of a US contractor. He has been responsible for attacks on Americans since the 1980s, as has Khazali, who was held at Camp Cropper in 2007. But it was Muhandis who was always the head of the powerful Iranian support for a network of militias in the region that helped guide this policy. He was key to supporting Hezbollah and had worked closely with Imad Mughniyeh – of Hezbollah and allegedly leader of Lebanon’s Islamic Jihad. Mughniyeh was assassinated in 2008.It is difficult to anticipate Iran’s response, but the regime will want to respond – not only to this attack, but also to the earlier US attack on December 29 that killed two dozen members of Kataib Hezbollah.That series of five airstrikes in Iraq and Syria is now overshadowed, but it was important because it demonstrated that the US would respond to Iran’s provocations.Since May, Iran has been attacking not only the US but also Israel, Saudi Arabia and oil tankers in the region. It downed a US drone and sent proxies in Iraq to fire rockets at least 12 times at US bases. These rocket attacks targeted key facilities – including the Green Zone, Camp Taji, Assad and Balad bases, and Qayarrah.Iran fired rockets at Israel in January, September and November of 2019 and attacked Saudi’s Abqaiq facility in September with a drone swarm. It also sent Kataib Hezbollah to attack Saudi Arabia in May, and to establish bases and arms trafficking networks across Iraq.In Syria, Iran built a new base, called Imam Ali, at the border with Iraq.In short: Iran’s activities in 2019 were accelerated and represented an increasing threat to Iraq, Syria, Lebanon and Yemen, as well as a threat along 5,000 km. of front line from the Lebanese border with Israel to the Gulf of Oman and Yemen. Soleimani was a key part of constructing Iran’s threats along this line. Muhandis was, as his name suggests, the engineer who helped build up Iran’s role in Iraq and also into Syria.THESE MEN – Soleimani, Muhandis and their network – were personally austere and frugal. They dressed in almost everyday clothing without chests festooned with a salad of medals. They went among both the civilian population and among their own men as one of them. They were often mild in their manners.Videos of Muhandis show him relaxing, laying on the ground to catch a few seconds nap and speaking softly. These men represented a dangerous threat not because of their boasts but because of their practicalities and decades spent honing their abilities.Soleimani was born in 1957; Muhandis in 1954. They were in their twenties during the Iranian Islamic Revolution, making it a formative moment in their lives; the revolution guided their lives from then on. For them, the US and Israel were the main enemies; they were the “resistance.”Saudi Arabia and other countries were also counted among their enemies, but they focused their zeal toward removing Western powers and advancing Iran’s interests and the interests of a wider Iranian-aligned Shi’ite community.In the 1980s, Muhandis and those like him supported terrorism against US diplomatic facilities from Kuwait to Lebanon. This was their field of operations. It took them some time, but they successfully built up franchises such as Hezbollah in Lebanon and Kataib Hezbollah in Iraq.Only after 2010 could their long-held dreams finally be realized. In the wake of the Arab spring and the chaos unleashed, they mobilized men to confront the ISIS threat and filled its vacuum with their own bases and fighters. This is how Kataib Hezbollah of Iraq ended up in Syria with Hezbollah.It was only in the last two years that their dream of a Middle East dominated by Iran was fulfilled. They were arrogant – the kind of arrogance they accused the West of. No longer in the shadows, those like Soleimani and Muhandis came into the open, where they acted like heads of state.Their militias in Iraq, called the Popular Mobilization Units (PMU), appeared to dominate not only the security forces but also the parliament: they had the second largest party in Iraq and access to 300,000 men they had recruited, most of whom were just young Shi’ites who wanted to fight ISIS.A smaller cadre of men in the PMU brigades was what mattered; they stockpiled munitions and, since August 2018, have been moving Iranian ballistic missiles across Iraq to Syria.In Syria, they built a network of bases from Imam Ali to T-2, T-4 and others. This network sought to transfer precision guided munitions to Hezbollah in Lebanon; it also sought to import an air defense system, the 3rd Khordad system, in April 2018.Consequently, Israel carried out more than 1,000 airstrikes against Iranian entrenchment in Syria, and Chief of Staff Lt.-Gen. Aviv Kochavi said in December that Israel would act against Iranian entrenchment in Syria and Iraq.FOR SOLEIMANI and Muhandis, all was well in December, even as US rhetoric increased. They did not believe the US would decisively respond, as Pompeo threatened. They had seen national security adviser John Bolton and other Iran hawks come and go, and had judged US President Donald Trump to be an isolationist.Consequently, they tried to push the US, via attacks in the Gulf and against Saudi Arabia, and then against US forces, carrying out 11 attacks on US bases since October, according to US sources.Finally, after the killing and wounding of Americans, the US acted by carrying out the December 29 strikes.Kataib Hezbollah responded two days later with the attack on the US embassy. Working with Badr Organization commander Hadi al-Amiri, who plays a role in the PMU and parliament, they opened the gates to the Green Zone, and PMU members in fatigues assaulted the embassy. They wrote “Soleimani is my leader” on the guardhouses. It was a symbol. They were saying that Soleimani runs Iraq and Baghdad, not the US.Forty-eight hours later, Soleimani and Muhandis were targeted in an airstrike near the airport. It is a fitting end to men who believed there would be no response to provocations. It will be a blow to their organizations and network, just as the killing of Mughniyeh was a blow.But they still have cadres and loyalists. Qais Khazali, Hassan Nasrallah and Hadi al-Amiri are still in Iraq and Lebanon. There are powerful people in charge of Iran’s IRGC, and it has developed new drone and missile technology.Nevertheless, the US has sent a powerful message: that killing Americans will not be tolerated.