
Johnson ran for President in his own right in 1964. He defeated Senator Barry Goldwater of Arizona, and received 61.1% of the popular vote. Johnson won the largest share of the popular vote of any candidate since the largely uncontested 1820 election.
Johnson began his elected presidential term with plans to continue his "Great Society" goals. His next pursuit in the field of civil rights was in the area of voting rights. In 1965, he achieved passage of a second civil rights bill called the Voting Rights Act, which outlawed discrimination in voting, allowing millions of southern African Americans to vote for the first time. The Senate passed the voting rights bill by a vote of 77–19 after 2 1/2 months, and it won passage in the house in July by a vote of 333 to 85. Between the years of 1968 and 1980, the number of southern African American elected state and federal officeholders nearly doubled.
After the murder of civil rights worker Viola Liuzzo, Johnson went on television to announce the arrest of four Ku Klux Klansmen implicated in her death. He angrily denounced the Klan as a "hooded society of bigots". Johnson was the first President to support the arrest and prosecution of members of the Klan since Ulysses S. Grant nearly a century earlier. In a speech at the Howard University commencement address on June 4, 1965, he said: "To shatter forever not only the barriers of law and public practice, but the walls which bound the condition of many by the color of his skin. To dissolve, as best we can, the antique enmities of the heart which diminish the holder, divide the great democracy, and do wrong—great wrong—to the children of God."
In 1967, Johnson nominated civil rights attorney Thurgood Marshall to be the first African-American justice of the Supreme Court. To head the new Department of Housing and Urban Development, Johnson appointed Robert C. Weaver, the first African-American cabinet secretary in any U.S. presidential administration. Then in 1968, Johnson signed the Civil Rights Act of 1968, which provided for equal housing opportunities regardless of race, creed, or national origin.
Johnson also made education the top priority of the Great Society agenda, with an emphasis on helping poor children. After the 1964 election, LBJ launched a legislative effort called the Elementary and Secondary Education Act (ESEA) of 1965. The bill sought to double federal spending on education from $4 billion to $8 billion. It passed the House by a vote of 263 to 153 on March 26, and passed without change in the Senate, by 73 to 8.
In 1965 Johnson turned his focus to hospital insurance for the aged under Social Security. His Medicare bill passed Congress on July 28 after negotiation in a conference committee. Johnson gave the first two Medicare cards to former President Harry S Truman and his wife Bess after signing the Medicare bill at the Truman Library in Independence, Missouri.
During Johnson's administration, NASA conducted the Gemini manned space program, developed the Saturn V rocket and its launch facility, and prepared to make the first manned Apollo program flights. On January 27, 1967, the entire crew of Apollo 1 was killed in a cabin fire during a spacecraft test on the launch pad. In spite of this tragedy, Johnson maintained his staunch support of Apollo through Congressional and press controversy, and the program recovered. The first two manned missions, Apollo 7 and Apollo 8 (the first manned flight to the Moon) were completed by the end of Johnson's term.
Johnson's second term was plagued with a number of major urban riots in African American neighborhoods. Riots broke out in the Watts district of Los Angeles in 1965. 34 people were killed and $35 million (the equivalent of $278.26 million in 2018) in property was damaged. In 1967, six days of riots in Newark left 26 dead, 1,500 injured. In Detroit in 1967, Governor George Romney sent in 7,400 national guard troops to quell fire bombings, looting, and attacks on businesses and on police. Johnson later sent in federal troops with tanks and machine guns. Detroit continued to burn for three more days, leaving 43 dead, 2,250 injured, 4,000 arrested. Property damage ranged into the hundreds of millions. The biggest wave of riots came in April 1968, in over a hundred cities after the assassination of Martin Luther King. Johnson's popularity plummeted as a result. Johnson created the Kerner Commission to study the problem of urban riots, headed by Illinois Governor Otto Kerner. Johnson told an aide that he was not surprised by the riots, saying: "What did you expect? I don't know why we're so surprised. When you put your foot on a man's neck and hold him down for three hundred years, and then you let him up, what's he going to do? He's going to knock your block off."
But the greatest problem for Johnson was the war in Vietnam. At the time of President Kennedy's death, there were 16,000 American military personnel stationed in Vietnam supporting South Vietnam in the war against North Vietnam. Vietnam had been partitioned at the 1954 Geneva Conference into two countries, with North Vietnam led by a Communist government. Johnson believed in the Domino Theory in Vietnam and to a containment policy that required America to make a serious effort to stop all Communist expansion.
In August 1964, allegations arose from the military that two U.S. destroyers had been attacked by some North Vietnamese torpedo boats in international waters 40 miles from the Vietnamese coast in the Gulf of Tonkin. Reports of the attack were contradictory. Johnson sought and obtained from the Congress the Gulf of Tonkin Resolution on August 7. The resolution gave congressional approval for use of military force by the commander-in-chief to repel future attacks and also to assist members of SEATO requesting assistance. The public's reaction to the resolution at the time was positive. 48% favored stronger measures in Vietnam while only 14% wanted to negotiate a settlement.
By the end of 1964, there were approximately 23,000 military personnel in South Vietnam. U.S. casualties for 1964 totaled 1,278. In the winter of 1964–1965 Johnson was pressured by the military to begin a bombing campaign to forcefully resist a communist takeover in South Vietnam. Polls at the time were in favor of military action against the communists. Johnson decided on a systematic bombing campaign in February of 1965. The eight-week bombing campaign became known as Operation Rolling Thunder. In March, Johnson approved an increase in logistical troops of 18,000 to 20,000 and the deployment of two additional Marine battalions and a Marine air squadron, in addition to planning for the deployment of two more divisions. He also authorized a change in mission from defensive to offensive operations; he nevertheless continued to insist that this was not to be publicly represented as a change in existing policy. By the middle of June, the total U.S. ground forces in Vietnam were increased to 82,000 or by 150 percent.
That same month, Ambassador Maxwell Taylor reported that the bombing offensive against North Vietnam had been ineffective, and that the South Vietnamese army was in danger of collapse. General Westmoreland recommended an increase in ground troops from 82,000 to 175,000. Johnson agreed to an increase to 125,000 troops, with additional forces to be sent later upon request. Johnson described himself at the time as having two bad choices: sending Americans to die in Vietnam and giving in to the communists. By October 1965 there were over 200,000 troops deployed in Vietnam.
Public and political opposition to the war began to grow in the spring of 1966. Johnson's approval ratings reached a new low of 41 percent. In response to the intensified criticism of the war effort, Johnson raised suspicions of communist subversion in the country. Press relations became strained. Senator William Fullbright, chairman of the Foreign Relations Committee, convened a series of public hearings in February to question a range of experts on the progress of war. Johnson began to seriously consider a more focused bombing campaign against petroleum, oil and lubrication facilities in North Vietnam in hopes of accelerating victory. By July polling results indicated that Americans favored the bombing campaign by a five-to-one margin. But in August a Defense Department study indicated that the bombing campaign had little impact on North Vietnam.
By the fall of 1966, Johnson was urged from every corner to begin peace discussions. In August, Johnson appointed Averell Harriman "Ambassador for Peace" to promote negotiations. In a discussion about the war with former President Dwight Eisenhower on October 3, 1966, Johnson said he was "trying to win it just as fast as I can in every way that I know how". By the end of the year it was clear that current pacification efforts were ineffective. Johnson then agreed to add 70,000 troops in 1967 to the 400,000 previously committed. he also agreed to an increase in the level of bombing, despite initial secret talks being held in Saigon, Hanoi and Warsaw. The bombing ended the talks, although North Vietnamese intentions were not considered genuine.
In January and February 1967, Ho Chi Minh declared that the only solution was a unilateral withdrawal by the U.S. A Gallup poll taken in July 1967 showed 52% of the country disapproving of the president's handling of the war and only 34% thought progress was being made. Robert F. Kennedy, who had become a prominent public critic of the war and loomed as a potential challenger in the 1968 presidential election. By the middle of 1967 nearly 70,000 Americans had been killed or wounded in the war. Johnson approved an increase of 55,000 troops bringing the total to 525,000. In August Johnson decided to expand the air campaign and exempted only Hanoi, Haiphong and a buffer zone with China from the target list. In September Johnson ceased bombing in a 10-mile zone around Hanoi in the hope that this would lead to further peace talks. In a Texas speech Johnson agreed to halt all bombing if Ho Chi Minh would launch productive and meaningful discussions and if North Vietnam would not seek to take advantage of the halt.

Johnson convened a group called the "Wise Men" for a fresh, in-depth look at the war. The group was made up of Dean Acheson, General Omar Bradley, George Ball, Mac Bundy, Arthur Dean, Douglas Dillon, Abe Fortas, Averell Harriman, Henry Cabot Lodge, Robert Murphy and Maxwell Taylor. At that time, Defense Secretary Robert McNamara, reversed his position on the war and recommended that a cap of 525,000 be placed on the number of forces deployed. He also recommended that the bombing be halted, since he could see no success. Johnson became agitated by this recommendation and McNamara's resignation soon followed. With the exception of George Ball, the "Wise Men" all agreed the administration should "press forward". Johnson believed that the North Vietnamese would not negotiate in good faith at any time before the 1968 U.S. election.
On June 23, 1967, Johnson traveled to Los Angeles for a Democratic fundraiser. Thousands of anti-war protesters staged a march past the hotel where he was speaking. Hundreds of LAPD officers were massed at the hotel and when the march slowed an order was given to disperse the crowd. 51 protestors arrested. Other massive protests which followed. Johnson gave no further public speeches in venues outside of military bases.In mid-October there was a demonstration of 100,000 at the Pentagon.
As casualties mounted and success seemed further away than ever, Johnson's popularity fell. College students and others protested, burned draft cards, and chanted, "Hey, hey, LBJ, how many kids did you kill today?" Johnson was not allowed by the Secret Service to attend the 1968 Democratic National Convention, where thousands of protesters converged. Support for Johnson continued to shrink. On January 30, the Viet Cong and North Vietnamese launched the Tet Offensive against South Vietnam's five largest cities, including Saigon and the U.S. embassy there and other government installations. The Tet offensive failed militarily, but it was a psychological victory, and it turned American public opinion against the war effort. Walter Cronkite of CBS news, voted the nation's "most trusted person" in February, expressed on the air that the conflict was deadlocked and that additional fighting would change nothing. Johnson was quoted as saying, "If I've lost Cronkite, I've lost middle America". Only 26% approved of Johnson's handling of Vietnam, while 63% disapproved. Clark Clifford, the new Defense Secretary, described the war as "a loser" and proposed to "cut losses and get out".
On March 31, Johnson spoke to the nation and announced an immediate unilateral halt to the bombing of North Vietnam. He also announced his intention to seek out peace talks anywhere at any time. At the close of his speech he said, "I shall not seek, and I will not accept, the nomination of my party for another term as your President".
Johnson decided to restrict future bombing. In April he succeeded in opening discussions of peace talks, and after extensive negotiations over the site, Paris was agreed to and talks began in May. The talks failed to yield any results. In October when the parties came close to an agreement on a bombing halt, Republican presidential nominee Richard Nixon intervened with the South Vietnamese, making promises of better terms, so as to delay a settlement on the issue until after the election.

Johnson was constitutionally permitted to run in the 1968 presidential election under the provisions of the 22nd Amendment. At first no prominent Democratic candidate was prepared to run against a sitting president of the Democratic Party. Only Senator Eugene McCarthy of Minnesota challenged Johnson as an anti-war candidate in the New Hampshire primary. On March 12, McCarthy won 42 percent of the primary vote to Johnson's 49 percent, a surprisingly strong showing for the little known Senator. Four days later, Senator Robert F. Kennedy of New York entered the race. By this time Johnson had lost control of the Democratic Party. After he announced he would not run for re-election, his approval ratings increased from 36 percent to 49 percent.
In what was termed the October surprise, Johnson announced to the nation on October 31, 1968, that he had ordered a complete cessation of "all air, naval and artillery bombardment of North Vietnam", effective November 1, should the Hanoi Government be willing to negotiate and citing progress with the Paris peace talks. In the end, Democrats did not fully unite behind Humphrey, enabling Republican candidate Richard Nixon to win the election.
History has viewed Johnson both through the lens of his historic legislative achievements, and his lack of success in the Vietnam War.