1968 Democratic Party presidential primaries
The 1968 Democratic presidential primaries were the selection process by which voters of the Democratic Party chose its nominee for President of the United States in the 1968 U.S. presidential election. Incumbent Vice President Hubert Humphrey was selected as the nominee in the 1968 Democratic National Convention held from August 26 to August 29, 1968, in Chicago, Illinois.

Candidates 
The following political leaders were candidates for the 1968 Democratic presidential nomination:

Nominee

Competed in primaries
These candidates participated in multiple state primaries or were included in multiple major national polls.

Bypassing primaries
The following candidates did not place their name directly on the ballot for any state's presidential primary, but may have sought to influence to selection of un-elected delegates or sought the support of uncommitted delegates.

Favorite sons
The following candidates ran only in their home state's primary or caucus for the purpose of controlling its delegate slate at the convention and did not appear to be considered national candidates by the media.

 Governor Roger D. Branigin of Indiana (endorsed Humphrey)
 State Attorney General Thomas C. Lynch of California (endorsed Humphrey)
 Senator George Smathers of Florida (endorsed Humphrey)
 Senator Stephen M. Young of Ohio (endorsed Humphrey)

Declined to run
The following persons were listed in two or more major national polls or were the subject of media speculation surrounding their potential candidacy, but declined to actively seek the nomination.

 Senator Ted Kennedy of Massachusetts
 Former Governor George Wallace of Alabama

Primary race
Though United States President Lyndon B. Johnson had served during two presidential terms, the 22nd Amendment did not disqualify Johnson from running for another term, because he had only served 14 months following John F. Kennedy's assassination before being sworn in for his 'full' term in January 1965. As a result, it was widely assumed when 1968 began that President Johnson would be a Democratic candidate, and that he would have little trouble in winning the Democratic nomination.

Despite the growing opposition to Johnson's policies in Vietnam in both Congress and in the public, no prominent Democratic politician was prepared to run against a sitting President of his own party. Anti-war activists of the new "Dump Johnson movement" initially approached United States Senator Robert F. Kennedy of New York, an outspoken critic of Johnson's policies with a large base of support, for a candidacy, but he declined to run. They then appealed to United States Senator Eugene McCarthy of Minnesota, who was willing to openly challenge Johnson; prior to entering the race, McCarthy had hoped that Kennedy would run as well. Running as an anti-war candidate in the New Hampshire primary, McCarthy hoped to pressure the Democrats into publicly opposing the Vietnam War. Trailing badly in national polls and with little chance to influence delegate selection absent primary wins, McCarthy decided to pour most of his resources into New Hampshire, the first state to hold a primary election. He was boosted by thousands of young college students who volunteered throughout the state, who shaved their beards and cut their hair to be "Clean for Gene."

On March 12, McCarthy won 42% of the primary vote to Johnson's 49%, an extremely strong showing for such a challenger, and one which gave McCarthy's campaign legitimacy and momentum. In a surprise move on March 16, Robert F. Kennedy renounced his earlier support for Johnson and proclaimed his own candidacy. McCarthy and his supporters viewed this as opportunism, creating a lasting enmity between the campaigns. To make matters worse, a poll in Wisconsin showed McCarthy beating the President badly, with the latter only getting 12% of the vote. Thereafter, McCarthy and Kennedy engaged in a series of state primaries. Despite Kennedy's high profile, McCarthy won most of the early primaries, including Kennedy's native state of Massachusetts and some primaries in which he and Kennedy were in direct competition. Following his victory in the key battleground state of Oregon, it was assumed that McCarthy was the preferred choice among the young voters.

Johnson withdraws
Johnson was now faced with two strong primary challenges.  In declining health and facing bleak political forecasts in the upcoming primaries, Johnson concluded that he could not win the nomination without a major political and personal struggle. On March 31, 1968, at the end of a televised address regarding the War, the President shocked the nation by announcing that he would not seek re-election.  By withdrawing from the race, he could avoid the stigma of defeat and could keep control of the party machinery to support Hubert Humphrey, his loyal Vice President. As the year developed, it also became clear that Johnson believed he could secure his place in the history books by ending the war before the election in November, thus giving Humphrey the boost he would need to win.

With Johnson's withdrawal, the New Deal Coalition effectively dissolved into support for different candidates:

 Hubert Humphrey, Johnson's Vice President, gained the support of labor unions and big-city party bosses (such as Chicago Mayor Richard J. Daley), who had been the Democratic Party's primary power base since the days of President Franklin D. Roosevelt. It was also believed that President Johnson himself was covertly supporting Humphrey, despite public claims of neutrality.
 McCarthy rallied students and intellectuals who had been the early activists against the war in Vietnam;
 Kennedy gained the support of  the poor, Catholics, African-Americans, and other racial and ethnic minorities;
 Conservative white Southern Democrats, or "Dixiecrats," their influence declining swiftly in the national party, tended to support either Vice President Humphrey or George C. Wallace and the Alabama governor's third-party campaign in the general election.

Contest for the Democratic nomination

After Johnson's withdrawal, Vice President Hubert Humphrey announced his candidacy on April 27. Kennedy was successful in four state primaries (Indiana, Nebraska, South Dakota, and California) and McCarthy won six (Wisconsin, Pennsylvania, Massachusetts, Oregon, New Jersey, and Illinois); however, in primaries where they campaigned directly against one another, Kennedy won three primaries (Indiana, Nebraska, and California) and McCarthy won one (Oregon). Humphrey did not compete in the primaries, leaving favorite sons to collect favorable surrogates, notably United States Senator George A. Smathers from Florida, United States Senator Stephen M. Young from Ohio, and Governor Roger D. Branigin of Indiana.

Humphrey's campaign concentrated on winning the delegates in non-primary states, where party leaders controlled the delegate votes. Kennedy defeated Branigin and McCarthy in the Indiana primary, and then defeated McCarthy in the Nebraska primary. However, McCarthy upset Kennedy in the Oregon primary.

After Kennedy's defeat in Oregon, the California primary was seen as crucial to both Kennedy and McCarthy. McCarthy stumped the state's many colleges and universities, where he was treated as a hero for being the first presidential candidate to oppose the war. Kennedy campaigned in the ghettos and barrios of the state's larger cities, where he was mobbed by enthusiastic supporters. Kennedy and McCarthy engaged in a television debate a few days before the election; it was generally considered a draw.  On June 4, Kennedy defeated McCarthy in California, 46% to 42%, and also won the South Dakota primary held the same day.  McCarthy, who defeated Kennedy in New Jersey that very same night, refused to withdraw from the presidential race and made it clear that he would contest Kennedy in the upcoming New York primary, where McCarthy had much support from antiwar activists in New York City.
 
After giving his victory speech at the Ambassador Hotel in Los Angeles, California, Kennedy was assassinated  in the kitchen service pantry in the early morning of June 5. A Palestinian immigrant with Jordanian citizenship named Sirhan Sirhan was arrested. Kennedy died 26 hours later at Good Samaritan Hospital. 
 
At the moment of Kennedy's death, the delegate totals were:

Hubert Humphrey 561
Robert Kennedy 393
Eugene McCarthy 258

Primaries
Only 14 states held primaries at this time (California, Florida, Illinois, Indiana, Massachusetts, Nebraska, New Hampshire, New Jersey, Ohio, Oregon, Pennsylvania, South Dakota, Wisconsin, and West Virginia) in addition to Washington, D.C.

Results by winners:

Statewide results by winner

Total popular vote:
 Eugene McCarthy - 2,914,933 (38.73%)
 Robert Kennedy - 2,305,148 (30.63%)
 Lyndon B. Johnson - 383,590 (5.10%)
 Hubert Humphrey - 166,463 (2.21%)
 Unpledged - 161,143 (2.14%)
Johnson/Humphrey surrogates:
 Stephen M. Young - 549,140 (7.30%)
 Thomas C. Lynch - 380,286 (5.05%)
 Roger D. Branigin - 238,700 (3.17%)
 George Smathers - 236,242 (3.14%)
 Scott Kelly - 128,899 (1.71%)
minor candidates and write-ins:
 George Wallace - 34,489 (0.46%)
 Richard Nixon  - 13,610 (0.18%)
 Ronald Reagan  - 5,309 (0.07%)
 Ted Kennedy - 4,052 (0.05%)
 Paul C. Fisher - 506 (0.01%)
 John G. Crommelin - 186 (0.00%)

Democratic Convention and antiwar protests

Robert Kennedy's death threw the Democratic Party into disarray. The loss of his campaign, which had relied on his popularity and charisma convincing non-primary delegates to support him at the convention, meant that the anti-war movement was effectively kaput, and that Humphrey would be the prohibitive favorite for the nomination.  Some of Kennedy's support went to McCarthy, but many of Kennedy's delegates, remembering their bitter primary battles with McCarthy, rallied around the late-starting candidacy of Senator George McGovern of South Dakota, a Kennedy supporter in the spring primaries.

When the 1968 Democratic National Convention opened in Chicago, thousands of young antiwar activists from around the nation gathered in the city to protest the Vietnam War. In a clash which was covered on live television, Americans were shocked to see Chicago Police officers brutally beating anti-war protesters. While the protesters chanted "the whole world is watching", the police used clubs and tear gas to beat back the protesters, leaving many of them bloody and dazed. The tear gas even wafted into numerous hotel suites; in one of them Vice President Humphrey was watching the proceedings on television. Meanwhile, the convention itself was marred by the strong-arm tactics of Chicago's mayor Richard J. Daley (who was seen on television angrily cursing Connecticut senator Abraham Ribicoff, who made a speech at the convention denouncing the excesses of the Chicago police in the riots).

In the end, the nomination itself was anticlimactic, with Vice President Humphrey handily beating McCarthy and McGovern on the first ballot. The convention then chose Senator Edmund Muskie of Maine as Humphrey's running mate. However, the tragedy of the antiwar riots crippled the Humphrey campaign from the start, and it never fully recovered. (White, pgs. 377-378;)

Source: Keating Holland, "All the Votes... Really," CNN

Endorsements

Hubert Humphrey
 President Johnson 
 Mayor Richard J. Daley of Chicago
 Former President Harry S. Truman of Missouri
 Entertainer Frank Sinatra

Robert Kennedy
 Senator Ralph Yarborough of Texas
 Senator Abraham Ribicoff of Connecticut
 Senator George McGovern of South Dakota
 Senator Ted Kennedy of Massachusetts, the candidate's brother
 Governor Harold E. Hughes of Iowa
 Senator Vance Hartke of Indiana
 Writer Norman Mailer
 Labor Leader Cesar Chavez
 Actress Shirley MacLaine
 Actress Stefanie Powers
 Actor Peter Lawford, the candidate's brother-in-law
 Actor Bill Cosby
 Musicians Sonny & Cher
 Musicians The Byrds
 Musician Bobby Darin
 Astronaut John Glenn
 Actor Robert Vaughn

Eugene McCarthy
 Representative Don Edwards of California
 Actor Paul Newman
 Actor Gene Wilder
 Musicians Simon & Garfunkel
George McGovern (during convention)
 Senator Abraham Ribicoff of Connecticut
 Senator Joseph S. Clark of Pennsylvania
 Governor Harold E. Hughes of Iowa