Had Obama not failed to enforce his chemical-weapons “red line” in Syria a year ago, following an attack on a suburb of Damascus, Russian President Vladimir Putin probably would not have been as daring as he was in Ukraine. Likewise, helping the Kurds to confront the Islamic State could send the right message to the Kremlin.
但西方需要重新审视自己的策略，因为这两项挑战具有相同点。假如奥巴马在一年前大马士革郊区袭击发生后坚持其化武“红线”，那么俄罗斯总统普京可能不会在乌克兰如此有恃无恐。同样，协助库尔德人抵抗“伊斯兰国”能对克里姆林起到警示作用。