The worst massacre in Israel’s history led to the deadliest war in Palestinian history, Iran’s first direct attacks on Israel, even the first time in any war that missiles had been intercepted in space. None of this would have happened without Mr Sinwar’s fateful decision last October. That is not to say the region would have been at peace—but this particular sequence of events would have been unthinkable had Hamas not killed more than 1,100 Israelis. Mr Sinwar wanted a cataclysmic war that would reshape the Middle East, and he got one.