On January 3, 2020, the Trump administration killed General Quassem Soleimani by a drone strike. Soleimani had been widely considered the second most powerful leader in Iran. President Trump and his administration have provided different justifications for the drone attack. The assassination of Quassem Soleimani has been met with criticism in many parts of the world. Legal scholars have extensively debated the lawfulness of the drone strike. They discussed, inter alia, whether the killing of the Iranian general was a violation of international law regulating the use of force (jus ad bellum), international humanitarian law (jus in bello) and international human rights law. The following article examines the legality of the killing of the Iranian general, from the jus ad bellum by focusing on the accumulation of events theory. Furthermore, the article addresses the policy implications that the killing of Soleimani might have on other countries such as North Korea.