As the Democratic nomination race shifts to the South and into states with more African American voters, the party’s white front-runners must directly confront the question of race and explain how their policies uplift black America. Each of them has been criticized for harboring a superficial understanding of American anti-blackness, if not manifesting outright racism. Amy Klobuchar has a questionable prosecutorial record; Joe Biden has drawn criticism for his voting record on civil rights legislation; Elizabeth Warren’s campaign was accused of marginalizing staffers of color, for which she apologized; and Bernie Sanders was criticized for conflating the conditions of poor whites with people of African descent.

But it is Pete Buttigieg, former mayor of South Bend, Ind., who arguably demonstrates the most consistent racial ignorance among his cohort. Not only does he hold a dismal record in representing the black residents of his municipality, but his past musings on race and the state of black America — from his 2011 discussion of young black kids failing due to the lack of role models, to his invocation of the “All Lives Matter” mantra just five years ago, to the recent accusations that his campaign uses black supporters as political props — expose shallow analysis of systemic racism throughout his political career.

To his credit, Buttigieg rarely tries to rationalize these remarks and promises to work through his past mistakes regarding race relations and systemic injustice. But his recent remarks invoking the legacy of Martin Luther King, Jr. should keep concerns about his commitment to addressing racism front and center. While Buttigieg encouraged Americans to “recommit” to King’s work, and asserted that we can realize King’s dream by building a future defined not by exclusion “but by belonging,” he repeated a common error committed by white Americans in King’s time and today. His posts said nothing of the specific plight of African Americans and appeared to invoke a colorblind vision of post-racial unity that many incorrectly ascribe to MLK.

For many on the left, Buttigieg represents the corporatist, moderate wing of the Democratic Party, in which candidates court donations from billionaires, support continued military engagements and reject the expansion of social programs. It is this demographic of “white moderates” that now-celebrated figures such as King vocally criticized. In 1967, King published his fourth book, “Where Do We Go from Here: Chaos or Community?” in which he called for equitable housing and education, condemned systemic inequities that left black people poor and marginalized and warned against craven allies who betrayed the principles of the civil rights movement. His message — both the ideas he advocated and the allies he warned against — still matter today for a Democratic leadership struggling to lead on issues of racial equality.

King argued that after the civil rights movement secured legal victories after the march on Selma, it needed to address the deeper structural issues of inequality: poverty, exploitation and discrimination against African Americans. This second phase of the movement, he claimed, never garnered widespread support among white liberals who had supported the quest for legal equality: “When Negroes looked for the second phase, the realization of equality, they found that many of their white allies had quietly disappeared.” King proposed that such abandonment revealed how the “ordinary white citizen” had more in common with the white segregationist than “either had with the Negro.” In other words, white people expressed support for the struggle but refused to push for radical social change, and they retreated from the ground-level organizing.

Elsewhere in “Where Do We Go from Here,” King wondered, “Why does white America delude itself … why does it rationalize the evil it retains?” Indeed, he noted that most white Americans “consider themselves” committed to justice for African Americans but drift away after the legislation is passed. Because white allies viewed legal segregation as the primary driver of inequality, they also assumed that the Voting Rights Act, the Civil Rights Act and the implementation of affirmative action solved the problem of racism.

But they didn’t. King cited the grim statistics confronting black Americans to show how by every socioeconomic measure, African Americans lagged far behind their white counterparts. In all positive areas of life, including housing, education and well-being, African Americans lagged behind whites by a whopping 50 percent. Similarly, by all negative measures, African Americans received a double share in comparison to European-descended Americans, including in black unemployment and infant mortality. In driving this point home, King poignantly declared, “When the Constitution was written … the Negro was 60 percent of a person. Today another curious formula seems to declare he is 50 percent of a person.”

What’s more, King noted, most white Americans still remained uncomfortable with full integration. Many rejected interracial marriage or even black people moving into majority-white neighborhoods. For all the legal victories won by civil rights activists, white Americans were reluctant to actualize the movement’s ultimate goals. As King put it: “A good many observers have remarked that if equality could come at once the Negro would not be ready for it. I submit that the white American is even more unprepared.”

In many respects, King was predicting sentiments expressed by Pete Buttigieg when the mayor admitted he was “slow to realize” that South Bend remained racially segregated into the 21st century. Buttigieg’s lack of urgency about remedying the systemic inequities faced by South Bend’s black population reflects how an indifferent white majority deals with racial friction: Ignore it and pretend it is irrelevant until it can no longer be ignored.

But King also presented a solution, one that Buttigieg and the other Democratic candidates need to understand: they must make a sustained effort to educate themselves out of racial ignorance. White allies must not abandon the quest for social and economic justice under presumptions that U.S. laws are enforced in a colorblind fashion.

King held a deep concern for everyone affected by poverty, and he actively recruited poor whites to join his “Poor People’s Campaign.” He also reflected glowingly on the white allies who risked everything to march with him, even if they were a small percentage of white Americans. His concern for the white poor allowed him to understand how different groups must work together and recognize their unique roles in the struggle, stating: “Negroes hold only one key to the double lock of peaceful change. The other is in the hands of the white community.”

When considering that the candidates for the Democratic nomination went from one of the most racially diverse groups in history to the remaining front-runners, all of whom are white, it is worth asking how these politicians can be held accountable for the promises they make to people of color whose votes they must win to secure the nomination. If Buttigieg hopes to be an ally and pursue social justice, he should study King’s radical model for a cross-racial alliance that, if truly realized, could set the path for authentic societal change. King recognized who shattered his dream, and if we want to repair it, we must reclaim the totality of his vision and work to fulfill it.