Prof. Efraim Inbar is wrong to argue that the West is better off with Islamic State organization maintaining its caliphate. On the contrary: Defeating IS and the horror it perpetuates requires nothing less than the elimination of its caliphate. Through control of territory, IS is able to inspire and train recruits, to direct terrorist attacks, and to demonstrate the West's inability to eradicate a pressing threat.
The Iranian regime can be considered rational, but it cannot be trusted with nuclear weapons. History has proven that radical regimes can seek the destruction of others if faced with an immense threat. Israel cannot rely on deterrence and must be prepared to confront Iran militarily or invest in ballistic missile defense.
Lost in the debate over Iran is the possibility that Iran is a rational actor that cannot be deterred. Iranian leaders may strike Israel with nuclear weapons if they feel they have nothing to lose.