Of the most feared terrorist leaders the United States has hunted and killed this century—from Osama bin Laden to Abu Bakr al-Baghdadi—no death ever had the significance of the one America just dealt. The killing of Iran’s Quds Force commander, Qassem Soleimani, in a U.S. strike yesterday in Baghdad wasn’t just the targeted assassination of a state military leader. It marked a dangerous new chapter in a roiling region Soleimani has helped shape for more than a decade, and moved the U.S. and Iran’s cycle of proxy violence and sabotage closer to outright war.

President Donald Trump did not immediately claim victory as he did for the death of Baghdadi in October. The president instead tweeted out a single image of an American flag as early reports of Soleimani’s demise circulated. The Defense Department confirmed that the U.S. military had killed Soleimani on Trump’s orders.

Soleimani has been called “the most powerful general in the Middle East today,” and the mastermind behind a strategy of backing sympathetic proxies in Yemen, Iraq, and Lebanon to secure influence and attack Iran’s enemies. Through the summer and fall of 2019, as the Trump administration ramped up its financial pressure campaign on Iran after leaving the nuclear deal, Soleimani’s forces or their proxies were blamed for attacks on oil tankers near the Persian Gulf, rocket volleys against American interests in Iraq, the shoot-down of an American drone, and a strike on an oil facility in Saudi Arabia.