The year 1968 was one of the most tumultuous in U.S. history. The nation was divided on multiple fronts, from the Vietnam War to the Civil Rights Movement to the Counterculture.

It was also an election year.

On the Republican side, former Vice President Richard Nixon was a front-runner against New York Governor Nelson Rockefeller and California Governor Ronald Reagan.

For the Democrats, incumbent President Lyndon Johnson was seeking re-election; however, after the fallout of the Tet Offensive earlier in the year and nearly losing the New Hampshire Primary to Minnesota Senator Eugene McCarthy, Johnson withdrew his candidacy on March 31. This opened the door for his vice president, Hubert Humphrey, to announce his candidacy.

As the former Mayor of Minneapolis and Majority Whip in the U.S. Senate, Humphrey was no stranger to politics. Even so, his nomination was not certain as he faced New York Senator Robert Kennedy, the brother of late President John Kennedy, and fellow Minnesotan Eugene McCarthy.

At the time, the Democratic Party was deeply divided over the Vietnam War. Kennedy and McCarthy ran on anti-war platforms, while Humphrey was associated with the Johnson administration, which escalated the conflict in Vietnam. While Kennedy had a strong following among the poor and minorities and McCarthy enjoyed support from students, Humphrey had the support of labor unions and big city party bosses. While Kennedy and McCarthy battled it out in primary states, Humphrey focused on winning delegates in non-primary states, aided by party leaders.

On June 4, Kennedy won the crucial California primary, giving him momentum to become the Democratic candidate. But after giving an early morning victory speech on June 5, Kennedy was shot by Sirhan Sirhan. He died 50 years ago today, in the early hours of June 6, 1968.

With Kennedy’s death, Humphrey emerged as the clear front-runner.

At the 1968 Democratic Convention in Chicago, Humphrey was nominated on the first ballot while 5,000 Vietnam War protesters clashed with police outside Convention Hall. The Democrats rejected a peace platform, choosing a pro-Johnson administration platform. In an attempt to unite the party, Humphrey said, “Let those who believe our cause in Vietnam has been right — and those who believe it has been wrong — agree here and now, neither vindication nor repudiation will bring peace or be worthy of our country.”

Humphrey’s candidacy was doomed from the start. Nixon was already ahead in the polls and Humphrey, dealing with party division, lack of funds and the violence in Chicago, tried to distance himself from the Johnson administration. In the Deep South, American Independent candidate George Wallace siphoned support away from Humphrey. A last minute endorsement from McCarthy and Johnson’s Oct. 31 order to end bombing in North Vietnam gave Humphrey a boost, but it was not enough. On Election Day, Humphrey received 191 electoral votes to Nixon’s 301.

Did Kennedy’s death change the dynamic of the race? It’s hard to say. At the time of Kennedy’s death, he trailed Humphrey in the delegate count, but not all delegates had been pledged. If Kennedy had won the nomination, could he have accomplished what Humphrey could not? Could he have defeated Nixon, the same man who lost to his brother in 1960?

The answers are forever lost to history.