Historians have long wondered what would have happened had Robert F. Kennedy lived. What if he had continued his 1968 presidential campaign? Could he have forged a political coalition that might have cauterized the nation’s racial wounds and arrested the slide into polarization? Could RFK have unified African Americans and working-class white folks behind the same political goals?

These what-ifs have received more than modest attention from historians. In 1968, RFK was “the last liberal who could reach both races as well as both generations,” wrote historian John Morton Blum. At the time of his assassination, Kennedy was beginning to construct “coalitions of supporters that cut across race and class lines,” historian James T. Patterson has argued. But beyond animating decades of historical scholarship and political analysis, the questions also emerged from a series of developments in 1968 that had begun to make Kennedy the unlikely face of a Black-white lower-income political coalition.

In 1967, antiwar activists urged RFK to mount a primary bid against Lyndon Johnson, but Kennedy refused. On March 16, 1968, however—four days after Sen. Eugene McCarthy nearly defeated LBJ in New Hampshire’s Democratic primary—Robert Kennedy declared that he, too, was seeking the Democratic nomination. His announcement speech made clear that his campaign agenda prioritized his opposition to the war over racial divisions and the problem of the cities. Kennedy denounced Johnson’s “disastrous, divisive [war] policy” and later charged that LBJ had abandoned “integrity, truth [and] honor” and “called on the darker impulses of the American spirits.”

Kennedy’s image as LBJ’s arch foe—the two men had had a long, bitter feud—infused his insurgent campaign with verve, and it seemed that Vietnam would be the issue that fired his candidacy. RFK, Johnson recalled, was seeking “to reclaim the throne in the memory of his brother. And the American people, swayed by the magic of the name, were dancing in the streets.”

Two events, a week apart, helped change the stakes for Kennedy’s campaign, raising the question of what was lost when Kennedy was assassinated. On March 31, two weeks after RFK had entered the race, Johnson announced he would not seek his party’s nomination. Although Johnson’s decision helped clear a nominating path for Kennedy, it deprived his campaign of its chief foil and nemesis. Johnson’s announcement that he would step up peace negotiations with North Vietnam further let some of the air out of Kennedy’s campaign.

The murder of Martin Luther King, Jr., on April 4, 1968, altered Kennedy’s campaign agenda and his national political identity. The combination of Johnson’s withdrawal and King’s assassination elevated Kennedy as a leader in the struggle to tamp down the divisive forces that were fraying the social fabric. As riots erupted in more than 100 cities, Kennedy, ignoring the pleas of his aides and the police, went ahead and held a campaign rally in an African American neighborhood in Indianapolis. From atop a flatbed truck, Kennedy broke the news of King’s murder, referenced his own brother’s assassination and vowed to continue the quest to achieve national understanding and racial reconciliation.

His speech cemented his image as a leading liberal seeking to maintain people’s faith in American institutions and its political culture. Fearing threats on his own life, LBJ heeded the Secret Service’s advice and stayed away from King’s funeral. But Kennedy was there, leading the procession. Civil rights activist and King ally John Lewis later remarked: “I felt I had lost a friend, a big brother, a colleague” in the wake of King’s murder. “Somehow, I said to myself, ‘Well, we still have Bobby Kennedy.’”

Kennedy donned the mantle of moral leadership within much of the African American community. As historian Jeff Shesol wrote, “RFK recognized—and shared, by the time of King’s death—Black rage, resentment and desperation.” Sympathetic to the movement for Black power and cultural pride, RFK waged a presidential campaign that was predicated on the idea of using government to empower African Americans in the quest for social justice.

He was already building a track record on civil rights and social justice. As a New York senator, he helped pass community development legislation that empowered the Brooklyn neighborhood of Bedford-Stuyvesant. His platform featured modest planks: job training, investing in the cities, forging public-private partnerships that would help provide African Americans with a modicum of economic independence. RFK “had a real affinity for the hurt people of the world, the Blacks, the poor, the misunderstood young,” Gore Vidal, a critic, observed, and his campaign now drove that idea home.

Running in the Indiana primary, Kennedy generated overflow, rapt crowds in African American sections of the city of Gary. Black Americans were rallying behind Kennedy because, as his friend and aide Richard Goodwin wrote, “they knew he was on their side.” RFK was adroit at reaching other communities of color, too. He drew strong support from Mexican Americans after he visited Cesar Chavez who was fighting to organize and empower California’s farm workers. Also, “Indians saw him as a warrior, the white Crazy Horse,” one Native American activist recalled; RFK’s visits to Oklahoma and upstate New York reservations deepened his reputation as a leader in the wars against poverty and racism. Puerto Ricans in New York City also rallied to the Kennedy cause.

Historians have speculated about Kennedy’s political potential because from April 6 to the time of his own murder two months later, RFK was countering the political extremism and racial polarization that now defined American life. Kennedy came to represent hope for liberals, people of color and some working-class white people that a national leader could address their values and propose solutions to their social interests and economic needs.

Kennedy’s campaign stop in working-class white districts in Indiana—including areas where the segregationist Alabama governor George Wallace had done well in 1964—showcased Kennedy’s remarkable appeal across the color line. In his visits, so many supporters shook hands with him that by day’s end they were bloodied. His clothes were torn, his hair jostled; he was treated like a conquering hero. During those appearances, Kennedy never renounced his pro-civil rights, antiwar positions. Yet he did remind white working-class voters that as a former attorney general, he was pro-law-and-order. He called for an end to riots and lawlessness, prompting Republican candidate Richard Nixon to quip, “A lot of these people think Bobby is more a law-and-order man than I am!”

Kennedy also sang paeans to the values of hard work and adopted a set of ideas in which government would devote fewer resources to welfare payments and do more to empower workers in lifting up their own lives. That Kennedy—pro-racial justice, antiwar—could “attract the support of…working class white people” was nothing so much as “miraculous,” one commentator marveled.

Kennedy made his agenda explicit when he told the journalist Jack Newfield that, “We have to convince the Negroes and the poor whites that they have common interests.” Assailing the wealthiest Americans who evaded paying their share of taxes, Kennedy touched a chord with Indiana’s white lower-income electorate. They liked RFK because they sensed “that he stood for those who were disadvantaged—not so much economically...but because their opportunities were unfairly limited, their way of life held in disdain, barricaded by the affluent middle classes,” explained Goodwin.

Kennedy “was not going to backtrack on his commitment to civil rights or his commitment to pursuing peace in Vietnam,” Century Foundation Senior Fellow Richard D. Kahlenberg has written. “But he would augment the pursuit of racial justice and peace with a commitment to toughness—on crime, on welfare and on national security.” He gave “working-class whites and Blacks the sense that he respected their American values as well as their interests.”

What Kennedy offered was not necessarily centralized government solutions to the nation’s intractable social and economic problems. Rather, he wished to use government to provide “incentives and opportunities,” as one RFK aide put it. “What the people in our ghettos need is…independence, not the charity and favor of their fellow citizens, but equal claim of right and equal power to enforce those claims,” RFK argued.

In Indiana, Kennedy drew large, adoring crowds in Black districts, and he won sizable majorities in some white ethnic precincts that had voted strongly for Wallace in 1964. In the Nebraska, South Dakota and California primaries, Kennedy assembled winning coalitions that married support from lower-income white people with majority votes from communities of color.

Had Kennedy not been murdered by an Arab nationalist, he likely still would have faced long odds in the presidential contest. Besting Vice President Hubert Humphrey, Johnson’s handpicked successor, to win the nomination would have been difficult. Defeating Nixon in November would have also been less than a sure bet. But there is a reason why over the past five decades so many liberals, scholars and political analysts have pondered what might have been. Kennedy spoke up against the war and in favor of civil rights. He brandished the theme of law and order, and offered solutions that relied less on Great Society programs than they did on plans to empower individuals through incentives.

History flows as much from structural factors, grassroots organizing and bottom-up developments as it does from the practice of high politics—campaigns and state-centered decisions. Nonetheless, more than a half-century later, it's easier to see why Kennedy’s all-too-brief campaign has achieved such mythic status. Goodwin put it well when he explained what was lost when Kennedy was killed. “[RFK] alone among white American politicians might have been able to heal the widening divisions between Black Americans and lower-income whites, between the hopeful young and a middle class that was turning away from hope,” Richard Goodwin wrote in his memoirs. “Bobby,” he added, “had the possibility of greatness.”

Matthew Dallek is associate professor at George Washington’s Graduate School of Political Management and author of several books, including Defenseless Under the Night: The Roosevelt Years and the Origins of Homeland Security.