America First? How Do We Know If President Trump Fulfills His Promise?

Donald Trump wants American corporations to invest in America, and he’s promised to enact policies that will make America First. So how do we measure whether he’s successful? I don’t know, but I’ll toss out a possible metric:

During the past eight years, US corporations invested about $300 billion overseas each year. If Trump is successful, this number should go down.

Or, perhaps some ratio would be a better measure: foreign investment as a percent of total investment. Or maybe something entirely different. In fact, I’m mostly publishing this as a provocation: if this is the wrong measure, what’s the right one? What’s the best way of knowing if US corporations start to direct more of their investment dollars into domestic expansion instead of building or buying overseas? Any trade economists want to weigh in on this?