This paper examines why the United States persists in taxing corporate income twice -- once at the corporate level and again at the shareholder level. The continued imposition of double taxation is puzzling: the double tax is widely recognized as being but unfair and inefficient, and it places a substantial burden on a powerful interest group, publicly-held corporations. Nevertheless, proposals to eliminate the double tax by integrating the corporate and individual tax invariably die a quiet death. We argue that the resilience of the corporate tax is a manifestation of the most enduring source of problems in corporate law, the separation of ownership and control in publicly-held corporations. As a result of this separation, shareholders and managers often have divergent objectives: in particular, managers are more concerned with promoting new investments. Accordingly, managers do not lobby in favor of integration because it creates a windfall for old capital; rather they lobby for benefits to new capital such as Accelerated Depreciation and Investment Tax Credits. Moreover, some managers will actively oppose integration because they benefit from the retained earnings trap created in certain circumstances by the double tax.