1950-1983 1950 North Korea invades South Korea, June 25. 1950 Pusan Perimeter formed, Aug 2. MacArthur invades at Inchon, Sep 15. 1951 22nd Amend. limits president to 2 terms: Proposed by Thomas Jefferson. 1951 Truman fires General Douglas MacArthur, April 11. 1951 UNIVAC introduces first commercial electronic computer system. 1953 Dwight D. Eisenhower takes oath on Jan. 20: 34th President. 1953 Stalin dies: Khrushchev new leader in U.S.S.R. 1953 Cease fire in Korea, 3 mile area becomes demilitarized zone (DMZ). 1954 Brown v. Board of Education of Topeka overturns Plessy v. Ferguson. 1954 Remington Rand sells a UNIVAC computer system to General Motors. 1955 Dr. Jonas Salk proves his vaccine against polio virus is safe. 1957 Dwight D. Eisenhower takes oath on January 20; begins 2nd term. 1957 Eisenhower authorizes, support assistance for South Vietnam. 1957 Sputnik satellite launched into orbit by Soviet Union. 1959 Alaska admitted as 49th state on Jan 3. 1959 St. Lawrence Seaway opens Great Lakes to foreign shipping, Apr 25. 1959 Hawaii admitted as 50th state on Aug 21. 1960 23rd Amendment grants Electoral College representation to Washington, DC. 1961 John F. Kennedy takes oath on January 20; becomes 35th President. 1962 John Glenn is first U.S. astronaut to orbit earth, Feb 20. 1962 Military aid begins in South Vietnam 1963 Rev. Martin Luther King, Jr., gives "I Have A Dream" speech on Aug 28. 1963 John F. Kennedy assassinated, Lyndon B. Johnson 36th President. 1964 24th Amendment ends poll taxes. 1964 Civil Rights Act puts teeth in Federal enforcement of anti-discrimination. 1964 Tonkin Gulf Resolution, August 24; big lie repealed in 1970. 1965 Lyndon B. Johnson takes oath, January 20; begins 1st full term. 1965 First American ground forces arrive in South Vietnam. 1967 25th Amendment allows President to step aside temporarily. 1967 Thurgood Marshall: first black justice on Supreme Court. 1968 Rev. Martin Luther King, Jr. murdered in Memphis. 1969 Richard M. Nixon takes oath on January 20: 37th President. 1969 Neil Armstrong took "one giant leap for mankind" onto the moon. 1969 Concorde, supersonic transport, commercial SST: 1st test flights. 1970 Four students killed by National Guard: campus protest at Kent State U. in Ohio. 1971 26th Amendment provides voting at 18 years old. 1972 Equal Rights Amendment for women proposed by Congress; never ratified. 1973 Richard M. Nixon takes oath on January 20; begins second term. 1973 VP Agnew forced to resign. Gerald R. Ford: 1st non-elected VP. 1973 Vietnam War ends for U.S. soldiers on March 29, as U.S. stops fighting. 1973 Wars Powers Act enacted into law, over veto of President Nixon. 1973 Roe v. Wade: starts bitter abortion/anti-abortion debates. 1974 Nixon resigns in disgrace. Gerald Ford becomes 38th President. 1975 Congress reneges on financial aid, to South Vietnam. 1975 The fall of Saigon, April 30, the United States quits. Surrenders Vietnam, Cambodia, and Laos, to Communist. 1975 The first personal computer, the Altair, is developed. Two years later Jobs and Wozniak introduce Apple II. 1976 Air France and British Airways begin 1st passenger SST service. 1977 James Earl "Jimmy" Carter becomes 39th President. Jan 20. 1979 PA's 3 Mile Island, Mar 28. Nuclear power plant in near melt down. 1979 SALT II Treaty signed with USSR but not ratified by U. S. Senate. 1980 Mount St. Helens volcano erupts in northwestern United States. 1981 Ronald W. Reagan takes oath January 20; becomes 40th President. 1981 Sandra Day O'Connor: 1st woman U.S.S.C. justice. Appointed by Reagan.