((a)) ** In general** Every individual (other than a nonresident alien) whose income tax liability for the taxable year is $3 or more may designate that $3 shall be paid over to the Presidential Election Campaign Fund in accordance with the provisions of section 9006(a). In the case of a joint return of husband and wife having an income tax liability of $6 or more, each spouse may designate that $3 shall be paid to the fund.

((b)) ** Income tax liability** For purposes of subsection (a), the income tax liability of an individual for any taxable year is the amount of the tax imposed by chapter 1 on such individual for such taxable year (as shown on his return), reduced by the sum of the credits (as shown in his return) allowable under part IV of subchapter A of chapter 1 (other than subpart C thereof).

((c)) ** Manner and time of designation** A designation under subsection (a) may be made with respect to any taxable year—

((1)) at the time of filing the return of the tax imposed by chapter 1 for such taxable year, or

((2)) at any other time (after the time of filing the return of the tax imposed by chapter 1 for such taxable year) specified in regulations prescribed by the Secretary.