The U.S. middle class is in dire need of revitalization.1 The poor and nearpoor face significant barriers to attaining middle-class status, while those in the middle class have seen a decline in their ranks and face a precarious future. Less than a decade ago, poor teenagers were advised to finish high school, go to work, and put off marriage and childbearing to secure their place in the middle class.2 Yet this approach was insufficient then and still is now. Only half of American children will outearn their parents, and the cost of living has only increased, limiting the stretch of those earnings.3 While other countries have seen a decline in the middle class, the problem is particularly acute in the United States. Why has middle-class status become so much harder to achieve and maintain? We examine some of the current working hypotheses and the evidence for these  explanations. A combination of factors—including the exportation and eliminationof jobs with good pay for those without a college degree, increasing educational requirements for existing jobs, the expense of achieving educational credentials