In his State of the Union address less than a month ago President Obama brought up a basic minimum corporate tax. He noted that “companies get tax breaks for moving jobs and profits overseas” and that American companies should not be allowed to use these mechanisms to avoid paying their fair share.

But in order to change this status quo, legislators need to close the loopholes that allow companies to drive down their effective tax rates far below the official rate. This needs to happen. There are far too many corporate tax loopholes—which are deductions, credits, and other tax expenditures that benefit certain activities—and they often result in very different marginal tax rates for different companies who conduct very similar business activities. It is these loopholes which allow corporations to pay an average rate of 12%, even though the statutory rate is 35%. It is these loopholes that allowed the 100 largest U.S. multinational corporations to pay about $16 billion of U.S. tax on approximately $700 billion of foreign active earnings in 2004 – an effective tax rate of about 2.3%.We must close these loopholes to align the effective corporate tax rate with the official rate.