Virginia responded to ratification of the Twenty-Fourth Amendment (banning poll taxes in federal elections) by giving voters a choice: pay a $1.50 poll tax or file a witnessed certificate of residency six months before every federal election. Chief Justice Warren held the certificate option an unconstitutional 'material requirement' that imposed a real burden solely on voters exercising their right not to pay a poll tax. The Amendment forbids not only poll taxes themselves but also cumbersome substitutes designed to accomplish the same disenfranchising end. Harman is the definitive judicial gloss on the Twenty-Fourth Amendment.