Civil Rights Act of 1964 and the Voting Rights Act of 1965. African Americans gained more civil rights and the power to exercise their voting rights. Voting rights for all races were protected by provisions of the Voting Rights Act. Martin Luther King Jr. assassination In contrast to the successes of the movement in Tennessee, the 1968 assassination of Martin Luther King Jr., in Memphis was perceived as symbolic of hatred in the state. King was in the city to support a strike by black sanitary public works employees of AFSCME Local 1733. The city quickly settled the strike on favorable terms to the employees. Riots and civil unrest erupted in African-American areas in numerous cities across the country, resulting in widespread injuries and millions of dollars in property damages. Latter half of 20th century In 1953, voters approved eight amendments to the state constitution, which extended the governor's term from two to four years, prohibiting two successive terms, and outlawed the poll tax. In the years following World War II, Tennessee's economy continued to industrialize, and demand for energy grew faster than ever before. TVA built additional dams and coal-fired power plants in the state during the postwar years. By the 1960s and onward, the state experienced economic growth due to the construction of the Interstate Highway System. Most of the state's interstates were completed by the mid-1970s. The construction of Interstate 40 through Memphis became a national talking point on the issue of eminent domain and grassroots lobbying, when the Tennessee Department of Transportation (TDOT) attempted to acquire Overton Park from the city of Memphis for the highway's right-of-way. A local activist group spent many years contesting the project and filed a series of lawsuits to stop the construction through the park. The case made its way to the U.S. Supreme Court in the 1971 landmark case Citizens to Preserve Overton Park v. Volpe. The court sided in favor of the activist group, and established the framework for judicial review of government agencies. In 1977, a state constitutional convention was held that recommended 13 amendments to the state's constitution, 12 of which votes approved the next year. The changes allowed governors to serve two consecutive terms, required the General Assembly to balance the state's annual budget, reformed county legislative bodies, and removed provisions that had been invalidated by federal legislation and court cases during the Civil Rights Movement.