Signed by Lyndon Johnson on August 6, 1965 in the immediate wake of Selma, the Voting Rights Act banned literacy tests and other race-based voting qualifications, authorized federal examiners and observers, and — most importantly — required jurisdictions with a documented history of discrimination (identified by a Section 4 coverage formula) to obtain federal 'preclearance' under Section 5 before making any election-law change. Black voter registration in the covered states rose from 29 percent in 1965 to more than 65 percent by 1970. In Shelby County v. Holder (2013) the Supreme Court struck down the Section 4 coverage formula, effectively suspending preclearance until Congress rewrites it — which it has not done.