Lyndon Baines Johnson (/ˈlɪndən ˈbeɪnz/; August 27, 1908 – January 22, 1973), often referred to by his initials LBJ, was an American politician who served as the 36th president of the United States from 1963 to 1969. He previously served as the 37th vice president from 1961 to 1963 under President John F. Kennedy, and was sworn in shortly after Kennedy's assassination. A Democrat from Texas, Johnson also served as a U.S. representative, U.S. Senator and the Senate's majority leader. He holds the distinction of being one of the few presidents who served in all elected offices at the federal level.

Instruction: Who is LBJ?
Response: Lyndon Baines Johnson (/ˈlɪndən ˈbeɪnz/; August 27, 1908 – January 22, 1973), often referred to by his initials LBJ, was an American politician who served as the 36th president of the United States from 1963 to 1969. He previously served as the 37th vice president from 1961 to 1963 under President John F. Kennedy, and was sworn in shortly after Kennedy's assassination. A Democrat from Texas, Johnson also served as a U.S. representative, U.S. Senator and the Senate's majority leader. He holds the distinction of being one of the few presidents who served in all elected offices at the federal level.

Born in a farmhouse in Stonewall, Texas, to a local political family, Johnson worked as a high school teacher and a congressional aide before winning election to the U.S. House of Representatives in 1937. In 1948, he won the 1948 Senate election in Texas after a narrow and controversial victory in the Democratic Party's primary. He was appointed to the position of Senate Majority Whip in 1951. He became the Senate Democratic leader in 1953 and majority leader in 1954. In 1960 Johnson ran for the Democratic nomination for president. Ultimately, Senator Kennedy bested Johnson and his other rivals for the nomination, then surprised many by offering to make Johnson his vice presidential running mate. The Kennedy-Johnson ticket won in the 1960 presidential election. Vice President Johnson assumed the presidency on November 22, 1963, after President Kennedy was assassinated. The following year Johnson was elected to the presidency when he won in a landslide against Arizona Senator Barry Goldwater, receiving 61.1% of the popular vote in the 1964 presidential election, the largest share won by any presidential candidate since the 1820 election.

Johnson's domestic policy was aimed at expanding civil rights, public broadcasting, access to healthcare, aid to education and the arts, urban and rural development, and public services. In 1964 Johnson coined the term the "Great Society" to describe these efforts. In addition, he sought to create better living conditions for low-income Americans by spearheading a campaign unofficially called the "War on Poverty". As part of these efforts, Johnson signed the Social Security Amendments of 1965, which resulted in the creation of Medicare and Medicaid. Johnson followed his predecessor's actions in bolstering NASA and made the Apollo Program a national priority. He enacted the Higher Education Act of 1965 which established federally insured student loans. Johnson signed the Immigration and Nationality Act of 1965 which laid the groundwork for U.S. immigration policy today. Johnson's opinion on the issue of civil rights put him at odds with other white, southern Democrats. His civil rights legacy was shaped by signing the Civil Rights Act of 1964, the Voting Rights Act of 1965, and the Civil Rights Act of 1968. During his presidency, the American political landscape transformed significantly, as white southerners who were once staunch Democrats began moving to the Republican Party and black voters began moving to the Democratic Party. Because of his domestic agenda, Johnson's presidency marked the peak of modern liberalism in the United States.

Johnson's presidency took place during the Cold War, thus his foreign policy prioritized containment of communism. Prior to his presidency, the U.S. was already involved in the Vietnam War, supporting South Vietnam against the communist North. Following a naval skirmish in 1964 between the United States and North Vietnam, Congress passed the Gulf of Tonkin Resolution, which granted Johnson the power to launch a full-scale military intervention in South East Asia. The number of American military personnel in Vietnam increased dramatically, and casualties soared among U.S. soldiers and Vietnamese civilians. Johnson also expanded military operations in neighboring Laos to destroy North Vietnamese supply lines. In 1968, the communist Tet Offensive inflamed the anti-war movement, especially among draft-age students on university campuses, and public opinion turned against America's involvement in the war. In Europe, Johnson's administration continued to promote and foster Western European political and economic cooperation and integration as his predecessors had.

At home, Johnson faced further troubles with race riots in major cities and increasing crime rates. His political opponents seized the opportunity and raised demands for "law and order" policies. Johnson began his presidency with near-universal support, but his approval declined throughout his presidency as the public became frustrated with both the Vietnam War and domestic unrest. Johnson initially sought to run for re-election; however, following disappointing results in the New Hampshire primary he withdrew his candidacy. The war was a major election issue and the 1968 presidential election saw Republican candidate Richard Nixon defeat Johnson's vice president Hubert Humphrey. At the end of his presidency in 1969, Johnson returned to his Texas ranch, published his memoirs, and in other respects kept a low profile until he died of a heart attack in 1973.

Johnson is one of the most controversial presidents in American history. Public opinion and academic assessments of his legacy have fluctuated greatly ever since his death. Historians and scholars rank Johnson in the upper tier because of his accomplishments regarding domestic policy. His administration passed many major laws that made substantial changes in civil rights, health care, welfare, and education. Conversely, Johnson is strongly criticized for his foreign policy, namely escalating American involvement in the Vietnam War.