U.S. President Donald Trump has a simple criterion to judge whether America benefits from international trade: Is America exporting more than it is importing? He applies this criterion country by country. If the U.S. has a bilateral current account deficit with a particular country, then it follows that this country is taking away jobs from Americans.
For some nations, such as Mexico, he threatens to respond by imposing a tariff. For others, he accuses them of manipulating their currencies. This opens up a new front in the still-simmering currency wars.