… is from Paul Krugman’s outstanding May 1993 American Economic Review essay “What Do Undergrads Need to Know about Trade?”, reprinted in Krugman, Pop Internationalism, pp. 117-125; this quotation is on page 124 of the latter:
Now there are reasons, such as external economies, why a preference for some industries over others may be justified. But this would be true in a closed economy, too. Students need to understand that the growth of world trade provides no additonal support for the proposition that our government should become an active friend to domestic industry.