You make my point. This tone you write about is a result of your perspective. From my perspective the writer states facts from the past and probabilities about the future. 

If last time there was more polarization and chaotic foreign relations why wouldn't there be next time?  

 Oh and I agree regardless of who holds POTUS that there will be more polarization. It will depend on who holds office for foreign relations, and potentially for improved peace, but I have no idea. I'm a subscriber to 4th turning principles and this was bound to occur anyways.