“Freedom of speech and action. Can live without fear, no Jim Crow.”

Those desires went little noticed. Indeed, it was resentment toward the Southerners’ arrival and obstacles to their entering the mainstream of Northern life that helped create the current conditions. Northern cities had had limited exposure to African-Americans. These cities were ill-prepared to absorb large numbers of asylum seekers who stood out from the rest of the population.

And so the newcomers were met with suspicion. Often recruited as strikebreakers, they were denied access to some unions and trades and were paid the lowest wages for the dirtiest work. They were roped off into overcrowded ghettos by means of redlining and periodic firebombings of homes purchased by black residents who breached the de facto wall of segregation.

Unlike the immigrants from Europe, they could not shield themselves from the assumptions about their heritage or blend into the majority just by Anglicizing their names or mastering the senator’s English. They stood out as the children of enslavement and Jim Crow, unable to escape the burden of a pained history.

It was a measure of how dire conditions were in the South that the Great Migration continued into the 1970s. When it began, 90 percent of all African-Americans were living in the South. By the time it ended, nearly half of all African-Americans lived elsewhere.

Notably, however, high profile-cases of police brutality have recently come to be associated with the North rather than the South. And it is in the South that two recent cases of police shootings of unarmed black people resulted in more vigorous prosecution. Last month, as protests raged over the deaths of Michael Brown in Missouri, Eric Garner in New York and John Crawford and Tamir Rice in Ohio, Randall Kerrick, a police officer in Charlotte, N.C., made his first court appearance on a charge of voluntary manslaughter in the 2013 death of Jonathan Ferrell. Mr. Ferrell was an unarmed black motorist who was shot 10 times as he sought help after a car accident. In September, Sean Groubert, a South Carolina state trooper, was fired after shooting an unarmed man, Levar Jones, during a traffic stop over a seatbelt violation. In a widely circulated video of the incident, Mr. Jones asked the trooper with humbling composure, “What did I do, sir?” Then: “Why did you shoot me?” He survived his injuries. The trooper was arrested and charged with aggravated assault and battery, a felony that carries a possible 20-year prison term.

The nation still has far to go, but this, at least, seems cause for hope. It suggests that the South, after decades of wrestling with its history, is now willing to face injustice head on. And it suggests that the North, after decades of insisting that it was fairer and more free, could eventually do the same.

It is not known what will come of the current upheaval in the North. The protests are a response to unprosecuted police brutality but are also a plea for recognition of African-Americans’ humanity. How can success be measured when the goals are so basic and enduring? History tells us that enough people acting together can have an impact beyond what could be imagined. The Great Migration changed American culture as we know it, produced jazz and Motown, playwrights and novelists, and transformed the social geography of most every city outside of the South. At the start of the movement, one of its chroniclers put the migrants’ aims in perspective. “If all of their dream does not come true,” The Chicago Defender newspaper wrote, “enough will come to pass to justify their actions.”

If the events of the last year have taught us anything, it is that, as much progress has been made over the generations, the challenges of color and tribe were not locked away in another century or confined to a single region but persist as a national problem and require the commitment of the entire nation to resolve.