International factors are no doubt a significant part of the backstory, because the same basic U-shape across the twentieth century is found in most advanced countries.62 Globalization is a plausible suspect, because international flows of people and goods and money tended to diminish in the first half of the twentieth century and then to intensify in the second half.63 Other Western countries have experienced the same international pressures, however, while seeing a much less dramatic increase in inequality, suggesting that U.S. domestic institutions and policies have played a major role.
