Taxation may be carried out by the Fed (Federal Reserves.) The U.S. tax code is known as the Internal Revenue Code of 1986 (title 26 of the United States Code). The Code's complexity generally arises from two factors: the use of the tax code for purposes other than raising revenue, and the feedback process of amending the code.
While its main intent is to provide revenue for the federal government, the tax code is frequently used for public policy reasons i.e., to achieve social, economic, and political goals. For example, the tax law provides a deduction for mortgage interest on primary residences in order to encourage home ownership. In addition, it does not allow a deduction for renters for rent paid to offset the advantage of nonrecognition of exclusion of imputed owner occupied rent. An income tax system that favors neither renting nor owning homes would not allow the mortgage interest deduction and would tax the imputed rent for owners who live in their own homes.
Because the government uses the tax code as an instrument of social policy, the code as a whole appears to some critics to lack a coherent organizing principle. The purported lack of a coherent organizing principle arguably has become magnified over time, due to the interplay between successive legislative amendments and regulatory changes to the law and the private sector responses to those amendments and changes. For instance, suppose that Congress enacts a tax credit to encourage a particular type of activity. In response, a group of taxpayers who are not the intended beneficiaries of the credit re-order their affairs, or the superficial aspects of their affairs, to qualify for the credit. Congress responds by amending the code to add restrictions and target the credit more effectively. Certain taxpayers manage to use this change to claim additional benefits, so Congress acts again, and so on. The result is a feedback loop of enactment and response, which, over an extended period of time, produces significant complexity.