If someone has an emotional preference for “American-made” products, however defined, that’s a sufficient reason for acting on the preference. Someone with that preference should not, however, kid himself that he is helping the American economy through his actions. Because a buy-America campaign would almost inevitably reinforce false economic premises–premises that would lead, as Jonah worries, to tariffs, preferences for American companies in government contracting, etc.–it would be worth keeping an eye on, so as to criticize it when it goes in that direction. In itself, it’s not objectionable.