Section 181 required voters to pass literacy tests in order to register, which were administered subjectively by white administrators to ensure most blacks were rejected. Section 180 was a grandfather clause, creating an exemption from the literacy test for anyone who had served in the military, or was descended from a veteran. As most slaves had been prevented from serving in the military, freedmen and their descendants could not take advantage of this clause, but many illiterate whites could. Section 194 required the payment of US$1.50 poll tax (Worth approximately US$37.74 by CPI). According to historian Glenn Feldman, by 1940 the cumulative poll tax had disenfranchised more poor white voters than blacks, but this was due to a larger white population; the black population was still disenfranchised at much higher rates than whites. These provisions were invalidated by the Voting Rights Act of 1965, which provided for federal oversight and enforcement of constitutional rights to suffrage.