The first section of the article discusses the central role of penal policy in democratic societies and the various ways that countries reconcile crime-control and due-process values. It concludes that, compared with other western countries, the United States has gotten the balance seriously wrong. The second section then reviews a range of general explanations for recent American penal policy trends and concludes that none of them explains enough. So far, at least, none of those in wide use can explain why countries subject to similar crime trends and social changes have varied so much in their reactions. The prevalent United States explanations make some sense of development in America, but not in other countries. The third section examines recent experience in the import and export of penal policies. The substantive effectiveness of policy innovations has little influence on whether they are adopted elsewhere. The United States in particular is neither a successful importer nor an influential exporter. More generally, countries in Western Europe actively emulate apparently successful innovation from elsewhere in Europe, but seem largely impervious to American influence. Common law countries, particularly England and Australia, have nibbled at replication of some, principally symbolic, United State policies, but half-heartedly, and they seem to pay little attention to what happens in Europe. The fourth section pulls together the conclusions of the preceding three sections and considers why there are pronounced national differences in penal policy, in the relative importance of symbolic and substantive policymaking, and in receptivity to ideas first developed elsewhere, as well as how understanding of such matters might be improved. 7 notes and 70 references