Last month, in his impromptu remarks on the Trayvon Martin ruling — in which the seventeen-year-old African American’s killer, George Zimmerman, was acquitted on charges of manslaughter and second-degree murder — President Obama repeatedly emphasized the notion of what he called a “very difficult history.” This was not merely the bitter reality of the African American experience, but the oft-unspoken narrative behind it — the “why,” as it were, not the “what.”

“You know,” the president said, “when Trayvon Martin was first shot, I said that this could have been my son. Another way of saying that is Trayvon Martin could have been me 35 years ago. And when you think about why, in the African-American community at least, there’s a lot of pain around what happened here, I think it’s important to recognize that the African American community is looking at this issue through a set of experiences and a history that — that doesn’t go away.”

That “history that doesn’t go away,” Obama was careful to mention, is part and parcel with a history of racial disparity in the application of this country’s criminal laws. In a sense, you could say that Martin died because of that history, that it is history that informs the stereotype of the “dangerous young black man” and history that causes the millions — yes, the millions — of George Zimmermans to continue to stalk the Trayvon Martins and not the other seventeen-year-olds sporting hoodies and bags of convenience store candy.

History lives, but history kills.

“Now,” the president added, “this isn’t to say that the African American community is naive about the fact that African American young men are disproportionately involved in the criminal justice system, that they are disproportionately both victims and perpetrators of violence. It’s not to make excuses for that fact, although black folks do interpret the reasons for that in a historical context.”

This historical context — or, rather, the lack of attention it is paid — is the fundamental problem with “stop and frisk,” the police tactic in use in many jurisdictions nationwide but made most famous in New York, where, after years of controversy, a federal judge ruled on Monday the application of the tactic unconstitutional. To be clear, she did not ban the use of stop and frisk out of hand; she merely reacted to the racial disparity at work in the stops the New York Police Department (NYPD) conducts. Those statistics are indeed arresting: Of the more than 4.4 million stops carried out between 2004 and 2012, African Americans and Hispanics account for more than 80 percent, although those groups represent only 62 percent of the city’s population.

Mayor Michael Bloomberg, a willing victim of the myopic incredulity that only great wealth can bring, has repeatedly brushed these numbers aside. What on earth, he wonders, is the issue? New York is safer, the murder rate has dropped to a historic low, and police, he has said on countless occasions, ought to stop those statistically more likely to commit a crime. As the emperor declared in what is surely one of the most inelegant public statements in recent memory: “We disproportionately stop whites too much and minorities too little.”

The problem is not that police officers in New York stop and frisk individuals on the street per se. Rather, the problem is that the city’s leadership has deliberately refused at every turn to offer any oversight or public accountability on a law enforcement tactic that, unmonitored, is an affront to civil liberties in every respect. Earlier this summer, the mayor’s office vetoed two provisions passed in City Hall that would have expanded the definition of racial profiling to allow individuals to sue in state court and installed an inspector general to supervise the policy. Both, he and his office suggested, were ridiculous.

All that accomplished was to laugh in the face of the history, the history that killed Martin and the history that, as Obama memorably noted, “doesn’t go away.” As it happens, laughing is one of the reasons that history endures, a quiet source of its strength.

In her 195-page ruling in Floyd v. City of New York, Judge Shira A. Scheindlin was mindful of that. Yes, her opinion mandated immediate changes to stop and frisk and installed an independent lawyer to oversee its application. But its primary emphasis was against what she called the “deliberate indifference” that has come to define New York’s handling of this issue. “In their zeal to defend a policy that they believe to be effective,” she wrote, “[the city’s leaders] have willfully ignored overwhelming proof that the policy of targeting the ‘right people’ is racially discriminatory and therefore violates the United States Constitution.”

The “proof” she mentions — the statistics, the numbers, the facts — is the evidence of the “history that doesn’t go away”; the “deliberate indifference” is the refusal, even now, to confront its shadow. It’s telling that in her conclusion, Scheindlin alluded to the Martin case and, specifically, the failure of the system to bend toward justice. Her task, of course, was merely to adjudicate stop and frisk, but here’s to hoping her opinion will also prevent the past from being so easily dismissed in the future.