Rev. Rul. 56-126

Where a Congressman returns a portion of his salary as a Member of Congress to the United States Treasury, which salary is payable at the rate specified by law and must be so paid in full, according to a recent ruling of the Comptroller General, the full amount of such salary is includible in his gross income for the taxable year in which received and constitutes wages subject to the withholding of Federal income tax. However, in computing his taxable income, a deduction is allowable as a charitable contribution for the amount returned to the Treasury to the extent provided in section 170 of the Internal Revenue Code of 1954. Such contributions are deductible only to the extent that the total deduction under section 170(a) of the 1954 Code for the taxable year does not exceed 20 percent of the taxpayer's adjusted gross income without regard to any net operating loss carry-back to the taxable year under section 172 of the 1954 Code.