Over the next four decades, this seemingly unqualified cleric who rose to the top almost by chance would become one of the world’s longest-serving autocrats, confounding every American president since George H.W. Bush. He would at one point become the most powerful man in the Middle East, dominating five failing lands — Syria, Lebanon, Iraq, Yemen and Gaza. This ambition and hubris also eventually led to his downfall. He came to govern with the hypervigilance and brutality of a man driven by the idea that much of his own society and the world’s greatest superpower sought to unseat him — which, in the end, it did. President Trump announced on social media that Ayatollah Khamenei was killed on Saturday. He was 86.