For the past 20 years, the best minds in Washington and Jerusalem treated Hamas as a pragmatic political operator whose leaders were satisfied living in the same world as the rest of us. Their charter, first adopted in 1988, endorsed a set of bloodcurdling millenarian goals. But despite the open madness and world-making ambitions of their public pronouncements, Hamas remained a semi-legitimate player, treated as just one unremarkable thread in the Middle East’s rich tapestry of mildly threatening, gun-toting political dreamers. Even to the most hardened Israeli security officials they were a Muslim Brotherhood offshoot whose extreme rhetoric and regrettably...