The Pentagon has confirmed that, at the direction of President Donald Trump, the United States military struck a convoy near Baghdad airport killing Maj. Gen. Qassem Soleimani, the notorious commander of the Iranian Revolutionary Guards Corps’ Quds force, and his Iraqi lieutenant, who is known by his nom de guerre Abu Mahdi al-Muhandis.At one stroke, the U.S. president has decapitated the Iranian regime’s chief terror arm and its most prominent extension in Iraq, where the U.S. Embassy was set on fire last week. Strategically, the killing of Osama bin Laden and, more recently, of ISIS leader Abu Bakr al-Baghdadi, pale by comparison. In addition to being responsible for killing hundreds of U.S. soldiers during the Iraq War, Soleimani directed a larger state project, which has shaped the geopolitics of the region.Soleimani, who arguably was the second most important man in the Iranian power hierarchy, led Iran’s military campaigns throughout the Middle East—campaigns that resulted in the lengthening of Iran’s shadow across Iraq, Syria, and Lebanon. The armies, militias, and terrorist groups that Soleimani directed, supported, trained, and equipped have killed hundreds of thousands of innocent civilians, devastated civilian infrastructure, and turned millions of people into refugees.Soleimani’s main job was commanding a network of Shiite militias subordinate to the Iranian Revolutionary Guards Corps (IRGC), which have served as the foot soldiers for his military campaigns. His subcommander in Iraq was al-Muhandis, an old Iranian asset who headed the Hezbollah Brigades and oversaw the so-called Popular Mobilization Units, the umbrella structure under which Iranian-controlled Iraqi militias were grouped. Over much of the previous decade, many of these militias were deployed in Syria, alongside the IRGC’s Lebanese unit, Hezbollah, to defend Iran’s interests there in support of the genocidal regime of the Syrian dictator Bashar Assad.Soleimani’s militias, which are integrated formally into the Iraqi security apparatus, have long been the real power in Baghdad. They also have taken advantage of U.S. support, especially during the Obama years, as part of the anti-ISIS campaign, to take control of large sections of the Iraqi border with Syria, which allowed Soleimani to move missiles, personnel, and other materiel across the border and point them at Israel’s head. Recent Israeli strikes along the Iraqi-Syrian border and inside Iraq are testament to Iran’s use of Iraqi territory in its broader geopolitical play, which includes the positioning of missiles on Iraqi and Syrian soil after having turned Lebanon into a forward missile base.Israel is hardly the only target. Soleimani also used Iraq as a forward base to target another U.S. ally, Saudi Arabia. This is the kind of strategic threat that only a state with large resources could pose, and which terror group leaders bin Laden and al-Baghdadi could only dream of while hiding in caves.Despite the size of the threat Soleimani posed, two U.S. presidents shied from taking him out. Even as Soleimani was harvesting American soldiers in Iraq with antitank missiles and roadside IEDs, President George W. Bush and his military commanders were too afraid to pull the trigger. Gen. Stanley McChrystal revealed a year ago how, when he was serving as the head of the Joint Special Operations Command in 2007, he had an opportunity to kill Soleimani, and very good reason to do so: “At the time, Iranian-made roadside bombs built and deployed at his command were claiming the lives of U.S. troops across Iraq.” But he didn’t, in order “to avoid a firefight, and the contentious politics that would follow.”A year later, another opportunity to kill Soleimani was wasted. During the operation to assassinate Hezbollah’s senior military commander, Imad Mughniyeh, in Damascus in 2008, Soleimani was present with Mughniyeh. “At one point, the two men were standing there, same place, same street. All they had to do was push the button,” a former U.S. official disclosed in 2015. “But the operatives didn’t have the legal authority to kill Soleimani … There had been no presidential finding to do so.”Seemingly immune from U.S. retaliation, Soleimani spent the Obama years strutting around Iraq and Syria like a peacock in ’70s-style turtleneck sweaters and an array of tailored military style jackets like an IRGC version of Al Pacino in Scarface, while garnering admiring magazine profiles.This nauseating treatment started at the top. Under President Obama, the U.S. was realigning with Iran, which meant providing its regime with billions of dollars, some of it hand delivered by U.S. officials in the form of large pallets of cash. The U.S. also provided direct military support to Soleimani’s Iraqi militias as part of the anti-ISIS campaign. It was important not to cross Iran’s red lines, administration officials regularly leaked at the time, so as not to jeopardize the safety of U.S. soldiers while they killed Iran’s enemies in Iraq and Syria–a strategy that was variously labeled as “counterterrorism” or “the fight against Al Qaeda” or “the war against ISIS,” and which invariably involved aligning with Iran to kill Sunni Arabs, who form the majority of the region’s population.Taking the red-carpet treatment for granted, Iran appears to have badly miscalculated with President Trump. The Trump administration had made clear last week that it would hold Iran directly accountable for any attack by its assets that harmed American personnel. The president personally tweeted that “Iran will be held fully responsible for lives lost, or damage incurred, at any of our facilities. They will pay a very BIG PRICE! This is not a Warning, it is a Threat. Happy New Year!”Not only did Iran and its militias kill an American in one such attack, but they then orchestrated an attack on the U.S. Embassy designed for maximum public humiliation. Al-Muhandis and other senior Iranian assets took part in the attack. Graffiti on the embassy walls declared Soleimani to be the attackers’ commander.There were no pretenses as to who was responsible for the attack. Iran’s head of state, Supreme Leader Ayatollah Ali Khamenei, who is often pictured with Soleimani at his side, publicly mocked the U.S., declaring that “You can’t do anything.” The stage was set for a replay of the Iranian U.S. Embassy takeover of 1979 in Tehran.Apparently, Khamenei, who according to Iranian regime doctrine exercises the authority of the missing 12th Shiite imam on earth, didn’t imagine what was coming next.After 15 years of Iran spreading its power throughout the region while degrading the U.S. strategic architecture in the Middle East and killing tens of thousands of people with impunity, President Trump attempted to stop the merry-go-round by disentangling the U.S. from Obama’s deal and reimposing sanctions on Iran. But the administration left some waivers in place, and there have been some mixed signals about negotiating a new nuclear deal with Iran. Apparently, neither Khamenei nor Soleimani was impressed.Now, Trump has shown that the U.S. is willing to strike back at Iran, and strike hard. What comes next is anyone’s guess, including possible Iranian strikes on Israel or on Saudi Arabia, Iranian strikes on U.S. troops in Iraq, anti-Iranian unrest inside Iraq, and anti-regime unrest within Iran itself, but one thing is already clear beyond any doubt: Iran can no longer expect to kill U.S. citizens and strike U.S. embassies with impunity.***Like this article? Sign up for our Daily Digest to get Tablet magazine’s new content in your inbox each morning.