Over the weekend, the Iranian military launched hundreds of drones and missiles toward Israel. Israeli, American, and Jordanian air defenses reportedly intercepted and shot down almost everything Iran fired. One child from a Bedouin village in southern Israel was hurt by shrapnel falling from an intercepted missile, and an Israeli air base in the Negev Desert—also in southern Israel—sustained some structural damage.

This attack was the widely expected response to an April 1 Israeli airstrike that destroyed the Iranian consulate in Syria. The Iranian government made it clear that it would seek revenge for the strike, which killed thirteen people, including two senior Iranian generals. In the weeks since that attack, many have worried that the Iranian response would spark an even larger Israeli reaction, escalating to the level of regional war and threatening to draw the United States in. That worry remains after Iran’s weekend attack.

Many parallels can be drawn to the escalatory cycle between the US and Iranian governments back in late 2019 and early 2020. And as we face another cycle of escalation, it’s worth looking back to see why things didn’t escalate to the point of war to help us understand how war can be avoided once again.

First, some important context. When the US invaded Iraq and overthrew Saddam Hussein in 2003, it removed the Iranian regime’s chief rival in the region. The Shia government that Washington then built up in Iraq was friendly with the Shia government of Iran.

In 2014, the Islamic State—which was then flourishing in eastern Syria thanks largely to US-provided money and weapons—moved into western Iraq and declared the area to be part of their new caliphate. Both the US and Iranian governments decided to directly join the fight against the Islamic State in Iraq and Syria (ISIS).

The US sent five thousand troops and provided air support to Iraqi forces. Iran sent its Quds Force, which armed, funded, and trained Shia militias called Popular Mobilization Forces. Together, this American-Iraqi-Iranian coalition drove ISIS completely out of Iraq by 2018.

But in 2019, Israel began launching airstrikes on these Shia militias in Iraq. Just as Iran is often blamed for the actions of groups it arms and funds, many Iraqis blamed the United States for the airstrikes because it arms and funds Israel.

So late in the year, some Popular Mobilization Forces began launching rockets at Iraqi bases where US troops were stationed. On December 27, 2019, a US contractor was killed in one of those attacks. In response, the US launched airstrikes on bases controlled by Kata’ib Hezbollah, the Shia militia Washington blamed for the rocket attack. After the airstrikes, Iraqi protesters stormed the US embassy in Baghdad and demanded that US troops leave Iraq.

Days later, in the early hours of January 3, 2020, the commander of Iran’s Quds Force, Qasem Soleimani, arrived in Baghdad to meet with Saudi Arabian officials as part of ongoing peace talks between the two Middle Eastern rivals. The Israeli government was not happy about the talks as, at the time, it was working to improve its own relations with Saudi Arabia in an attempt to turn it against Iran.

And so, according to the head of Israel’s Military Intelligence Directorate at the time, as Soleimani arrived at the Baghdad airport, the Israeli government told the Trump administration that the Iranian general posed an “immediate threat” to American soldiers and diplomats. Minutes later, on President Donald Trump’s orders, a US Reaper drone fired several missiles at Soleimani’s convoy as it left the airport. The Iranian general was killed, along with an Iraqi Popular Mobilization Force commander and eight other people.

Iraqi protesters immediately took to the streets, stepping up their demand for US troops to leave. In Iran, supporters of the regime called on their government to take revenge. Trump quickly warned that if Iran struck any American or American asset, he would launch strikes on fifty-two heritage sites “important to Iran and Iranian culture.”

At the time, it felt almost inevitable that war between the US and Iran would break out. The Iranian regime faced intense internal and external pressure to respond militarily to the assassination of Soleimani. And Trump was explicit that if they even so much as broke a pencil on an American base, he would launch missiles into Iran.

So, what happened? Something remarkably similar to what happened this past weekend.

On the night of Tuesday, January 7, 2020, Iran notified US officials that they were about to launch missiles at two bases in Iraq housing US troops. Hours later, videos were published showing a barrage of surface-to-surface ballistic missiles being fired from Iran.

Thanks to the advance warning, thousands of American troops were able to evacuate. But even those who remained fared relatively well as the missiles slammed into empty corners of the two targeted bases. A number of US troops suffered concussions and other brain injuries from the nearby blasts, but no one was killed or maimed in the attack.

Thankfully, Trump and his administration recognized the Iranian strike for what it was—an opportunity to de-escalate. The attack was a show of force strong enough to demonstrate that Iran could exert serious damage on American forces in the region. But it was also deliberately limited enough to allow the US to halt escalations without losing face. Trump took that opportunity. He did not order the strike he had threatened on Iran, and while relations between the countries remained tense, war was avoided.

Details are still coming out about Iran’s missile and drone attack on Israel early Sunday. But from what we know so far, Israel had hours of advance warning after Iran launched its drones from Yemen, Iraq, and Iran. The drones and missiles had to travel through Jordan, where American and Jordanian forces were able to get a head start intercepting and downing them before they even reached Israel. And the Iranians kept the beacon lights on their drones illuminated, making them easy targets for antiair systems.

That’s not to suggest that the attack was some sort of sham. The missile defense against this one attack reportedly cost Israel over a billion dollars. And, again, it appears that some Iranian missiles successfully struck Israel’s Nevatim Airbase in the Negev Desert, where Iran claims the strike on its consulate originated.

But the fact that no Israelis were killed, including at Nevatim, means that the Israelis and their backers in Washington have a sincere opportunity to halt this cycle of escalation and avoid an all-out regional war. As expected, hard-liners in both governments are calling to forgo this opportunity and to instead escalate things further with more retaliatory strikes on Iran. But if Joe Biden truly cares about the well-being of Americans, Israelis, and Palestinians—as he claims to—he should follow Trump’s lead, avoid a further escalation, and use all the leverage he has with Israel’s government to ensure they do the same. There may not be another opportunity.