Yesterday Iran launched more than a dozen ballistic missiles at U.S. forces based in Iraq. No Americans were reported harmed in the attacks. The salvo of missiles was in response to the U.S. assassination of Iranian general , killed in Baghdad by a Reaper drone strike. The two countries stand at the precipice of war, prompting the question of just exactly how did we get here?

The United States and Iran have had a long and turbulent history. In 1953, U.S. and U.K. intelligence that overthrew the regime of Iranian Prime Minister Mohammad Mossadegh. This led to the rule of the Shah, also known as Mohammad Reza Pahlavi, an autocratic and despotic monarch who was in turn deposed in the 1979 Iranian Revolution.

The revolution put the country under the control of a theocratic, Shiite regime that harbored a deep hatred of the United States for the 1953 coup and Washington’s efforts to prop up the Shah. In 1980 Iran was invaded by neighboring Iraq and the two countries to a standstill, with the war ending in 1988.

During the 1980s Iran and the United States fought something of a shadow war, with Iran supporting groups like Hezbollah, which in 1983 into a barracks building in Beirut, Lebanon, killing 241 U.S. Marines. In 1987, U.S. forces conducted , engaging Iranian forces at sea after an Iranian mine damaged the frigate USS Samuel B. Roberts.

The 1990s was a relatively quiet decade in U.S. and Iranian relations, though the continuing rule of Iran’s religious elites guaranteed enmity between the two countries. A revolutionary state, Iran’s government needed an external enemy that threatened the revolution, and the “Great Satan” served nicely. Still, the U.S. was largely absent from the Iranian landscape, and vice-versa.

In the early 2000s Iran started researching ballistic missiles and nuclear weapons, placing it on a collision course with the United States. At the same time the , a special operations and espionage arm of the Iranian Revolutionary Guards Corps (IRGC) began providing funding and to Iraqi guerrilla groups, resulting in the deaths of approximately 600 U.S. military personnel and thousands of American injuries. The Quds Force was headed by none other than Qassem Soleimani.

Iran in the 2010s became much more emboldened, intensifying its nuclear program and . Iran also . Tensions with the West were partially alleviated with the passage of the 2015 Joint Comprehensive Plan of Action (JCPOA), which throttled back Iran’s nuclear program by dismantling most of the country’s weapons-related nuclear capability.

In 2016 then-candidate Donald Trump campaigned against the treaty, claiming his “number one priority” was, “to dismantle the disastrous deal with Iran.” Trump withdrew the United States from the JCPOA in 2018 and of course, the better deal never actually happened. Now, it looks like it never will. Trump also , particularly those aimed at Iran’s banking, oil, shipping and ship-building sectors, and .

In 2019 Iranian forces staged several provocative encounters with the West. Iranian drones and gunboats began harassing U.S. Navy warships in the Persian Gulf. In June Iranian air defense forces a U.S. Navy RQ-4A Global Hawk drone Tehran claimed had violated its airspace. Washington did not retaliate for the loss of the $220 million unmanned aircraft. In July IRGC forces , and that same day U.S. Marines deemed to have come too close to an American warship.

In December, U.S. intelligence reportedly picked up warnings that Iranian forces were , directing attacks on U.S. targets. President Trump, National Security Adviser Robert O’Brien, and Chairman of the Joint Chiefs of Staff that Soleimani was planning attacks on Americans. The December 27, 2019 in a rocket attack by Iranian-backed militias appears to have been the last straw. President Trump made the decision to kill Soleimani. On January 3rd just outside Baghdad International Airport, the vehicle Soleimani was traveling in was struck by a Hellfire anti-tank missile launched from a MQ-9 Reaper drone.

Iran’s January 8th missile strike, code named Operation Martyr Soleimani, failed to kill any Americans. This might very well have been intentional, as the missiles directly struck structures holding equipment and not people. A working theory is that Iran struck back to say it could, but did so in a way that Washington would not feel compelled to retaliate—and escalate.

Meanwhile, other than a headcount, the U.S. military has done virtually nothing. That’s a remarkable level of restraint after the act of assassinating Soleimani. After the strikes, President Donald Trump met with Secretary of State Mike Pompeo, Secretary of Defense Mark Esper and Chairman of the Joint Chiefs of Staff Mark Milley but no immediate action was forthcoming. Trump took to Twitter to announce that there were no U.S. casualties in the attack.

What happens next? The last two actions in this crisis, the assassination of Soleimani and the direct attack on U.S. forces by Iran are both unprecedented and make the crisis harder to game out. On one side is a bombastic, insecure U.S president with virtually unlimited power. On the other side are intractable enemies of the United States with very limited power who are probably taking Soleimani’s killing very personally.

Will the crisis escalate into a wider war? Neither side appears to actually want war, and the lack of an immediate response from the U.S. indicates Washington is weighing its options—particularly the option to do nothing. The lack of American casualties in Operation Martyr Soleimani gives the Trump Administration an offramp to de-escalate, shrugging the attack off as inconsequential. Alternately, Trump could also retaliate.

Iran and the United States want fundamentally different things. Iran is in an expansionist period, attempting to carve out a sphere of influence in the Middle East. America, on the other hand wants a region dominated by Washington’s Arab allies, including Saudi Arabia, the UAE, and other more minor players. Iran believes it has time on its side, and it’s probably right. Long after the U.S. loses interest in the Middle East Iran will still be a major player—if not regional superpower. America’s allies and Iran’s neighbors know this, and Iran knows they know this.

Even without war, the events of the last week have probably bought another decade’s worth of bad blood between the two countries, the feud between Washington and Tehran nowhere near an end.