WASHINGTON—Experienced foreign-policy observers in the US capital have long learned never to make public predictions. The world is far too uncertain and the downside risks to your reputation are far too high if you end up well off the mark. It’s clearly advisable to wait until events have already transpired and then claim afterward that you saw them coming all along. This is especially the case when it comes to decisions to go to war. Yet those who carry the burden of policymaking are forced to make predictions to inform their policies. So even as negotiations continue between the United States and Iran, US President Donald Trump and his advisers are undoubtedly trying to assess what Iranian Supreme Leader Ayatollah Ali Khamenei will do in the face of the “massive […]