While the US and Iran have quarreled on the nuclear deal, they do share two major interests: they both don’t want a major war and want the US to disengage from the Middle East.US President Donald Trump stated these interests several times and demonstrated them by tolerating repeated violent provocations by Iran in the Gulf, allowing the Turkish invasion and occupation of territory in northern Syria, and withdrawing American forces from that area.Both countries expressed interest in negotiations to settle the conflict over the 2015 nuclear deal. During the last meeting of the UN General Assembly, Trump almost begged for a meeting with President Hassan Rouhani and was rebuffed because Iran set a precondition: an immediate removal of the harsh US sanctions, which Trump rejected.So the question is how did Iran and the US reach a direct violent confrontation that may be leading to a major war they both want to avoid?The answer may be found in missed perceptions and miscalculations, primarily on the Iranian side.The targeted killing of Qasem Soleimani wasn’t a retaliation for the attack of his Shi’ite militias on the US Embassy. This attack was only the straw that broke the camel’s back. Throughout the second half of 2019, Trump showed much restraint in the face of a series of violent provocations by Iran in the Gulf. In May, Iran attacked oil tankers, in June it downed an expensive American drone, and in September it attacked major oil facilities in Saudi Arabia. All these provocations were designed to counter the harsh US sanctions. Trump didn’t respond, to the chagrin of the US’s Arab allies and Israel.Soleimani misperceived and misinterpreted Trump’s intentions, took his aggressive designs one step too far and crossed sensitive redlines. Based on Trump’s statements and inaction in the Gulf and in northern Syria, Soleimani and his immediate superior and mentor, Ayatollah Khamenei, assumed that Trump was timid and, due to the forthcoming presidential elections in the US, wouldn’t dare risk a major war. They miscalculated and were caught by a strategic surprise. Trump indeed doesn’t want another entanglement in the region, but in an election year he can’t afford to look wimpy either and withdraw under Iranian military pressure.The difference between restraint and retaliation was the attack of Soleimani’s pro-Iranian militias on an American base in Baghdad and the killing of an American citizen. The same phenomenon occurred during the Obama tenure at the White House. He, like Trump, wanted to disengage from the Middle East. He felt forced to wage war against the Islamic State jihadists only when they began to behead American journalists and aid workers.Several international conventions, which both Iran and Iraq joined, define diplomatic missions as extraterritorial. The host country is forbidden entry to the premises of a mission without permission of the represented country, even to put out a fire. International rules also define an attack on an embassy as an attack on the represented country. Iran has violated these rules.An attack on a US diplomatic mission also touched a highly sensitive nerve in the history of American foreign policy. The chaotic desertion of the US Embassy in Saigon in 1975, the obliteration of the US Embassy in Tehran in 1979 and the holding of 52 American diplomats for 444 days, and the attack on the US diplomatic post and the CIA annex in Benghazi, Libya, in 2012 left serious scars on American prestige and honor. At the personal level, Khamenei infuriated Trump by telling him, You can’t do a damn thing.IT IS extremely difficult to forecast the next steps. Iran promised painful retaliation against the US and its allies. If Tehran pursues harsh revenge, Trump would have to respond in kind. A cycle of escalating retaliation may eventually lead to a major war but also to other scenarios, such as a US withdrawal from the region or negotiations over a new nuclear deal and an end to the conflict. Iran would like to see a Democrat win the 2020 presidential elections and may opt for measures that would help to secure this outcome.Regardless, the main lesson for the US from the recent exchanges of fire is to avoid mixed messages and confusing actions that often lead to misperceptions and miscalculations.The writer, a professor, is an expert on American politics and foreign policy and a senior research associate at the BESA Center for Strategic Studies at Bar-Ilan University.