While details have changed from time to time, the basic treatment of foreign source income in the United States tax code has remained essentially the same as that in 1918, when the foreign tax credit was introduced. All worldwide income is currently taxed, with a credit for foreign taxes paid, but income of subsidiaries incorporated in foreign jurisdictions is not considered part of that worldwide income until it is repatriated. As a result of a revision in 1962, certain passive income of foreign subsidiaries is subject to current taxation under Subpart F of the Internal Revenue Code. This system produces a number of economic distortions as well as opportunities for tax avoidance. Those continuing issues, along with the increasing integration of the global economy, have led to proposals for reform. These proposals fall roughly into four categories: narrow proposals aimed at tax avoidance concerns, proposals to move the system towards a pure territorial (or source-based) system, proposals to move the system in the opposite direction towards a current world-wide tax system, or proposals to retain the current system but lower the corporate tax rate with revenue offsets.In evaluating these proposed tax changes, two issues, which are related but nevertheless not identical, should be considered. The first is the real effects of current law and of a revision on economic activity. When investment responds to tax differentials, it affects the allocation of capital which in turn has implications for efficiency and income distribution (the extent to which the tax burden falls on capital versus labor incomes). In a closed economy with a fixed capital stock, the burden of the corporate tax falls on capital income in general. If the U.S. corporate tax does not apply in the foreign jurisdiction, capital can flow abroad with the result that some of the burden on the tax falls on labor (depending on the mobility of capital).3 Thus, the international tax system has implications for the overall welfare of the United States, and the world, and for the division of that welfare between those with primarily labor income, who tend to have lower incomes, and those with primarily capital income, who tend to have higher incomes.