It’s been called the population weapon, and it’s an effective way to blackmail Europe. The late Libyan dictator Muammar Gadhafi used it. So has Turkish President Recep Tayyip Erdogan. And now the government of President Abdel Fattah el-Sisi is threatening to do so, if the West continues to call for Egypt to accept refugees from Gaza. A senior Egyptian official quoted by the Financial Times…