Trump is right about one thing. The first 100 days benchmark is an arbitrary one. We can focus on the day-to-day shifts in his foreign policy, which flips and flops with a lot of bluster but without a guiding strategy. Doing so, however, may lead us to lose focus on the biggest shift in American foreign policy since World War II: from a series of qualified, measured and well-informed Presidents to a man who is none of the above. And that's the story that will continue to be most relevant for the next 1,360 days.