any strange deaths of leaders?

Rumors were that Roman Emperor Claudius was given poisoned mushrooms. He tried to throw up the shrooms, a physician crammed a feather down his throat to induce vomiting and he chocked on said feather.

King Charles II of Navarre liked scarves soaked in brandy to soothe his perpetually sore throat. An attendant noticed a loose thread and instead of cutting the thread, he tried to burn it off with a candle. Brandy and an open flame, predictable results.