This adage is worth recalling in February as U.S. President Donald Trump moves forward with replacing multinational trade alliances with a string of bilateral agreements. There are merits to his view and he comes by them honestly, but actions have consequences — especially when success means the world earns less and, if a U.S. trade surplus results, the world becomes a net exporter of income to the U.S. The world is unlikely to appreciate such a turn and will react in the best interests of its domestic politics .