the return of tax imposed by chapter 1 (determined without regard to extensions) or, if later, the date the return is filed, and (2) a contribution made by such taxpayer on such date to the United States. (d) Online contributions The Secretary shall establish and maintain a Web site through which persons may make contributions to the Freedom From Influence Fund. Any such contribution shall not be treated as an overpayment of tax but shall be treated as a contribution made by such person to the United States. . (b) Clerical amendment The table of parts for subchapter A of chapter 61 of the Internal Revenue Code of 1986 is amended by adding at the end the following new item: Part IX. Contributions to Freedom From Influence Fund . (c) Effective date The amendments made by this section shall apply with respect to tax returns required to be filed after December 31, 2016. VI Miscellaneous Provisions 601. Severability If any provision of this Act or any amendment made by this Act, or the application of a provision of this Act or an amendment made by this Act to any person or circumstance, is held to be unconstitutional, the remainder of this Act, and the application of the provisions to any person or circumstance, shall not be affected by the holding.