Announcing his presidential bid this month, Sen. Rand Paul said he wants to repeal “any law that disproportionately incarcerates people of color.”

Fulfilling this promise would require gutting murder statutes, and most other criminal laws, given the disproportionate black crime rate.

But whether or not Paul reaches the White House, a wide-ranging movement is already under way to transform the criminal justice system in order to avoid a disparate impact on blacks. This push will jeopardize the country’s two-decade-long crime drop.

The pretext for the current decriminalization movement is the half-dozen highly publicized deaths of blacks in encounters with police over the past nine months, including the recent case of Freddie Gray in Baltimore.

That case triggered looting and rioting Monday. But every police killing has been leveraged to argue for less enforcement and less consequences for unlawful behavior.

In New York City, the City Council is crafting legislation that would decriminalize such public-order offenses as turnstile-jumping, public urination and public drinking. (New York’s top judge, Jonathan Lippman, expressed general support for the effort on Monday.)

The proposed legislation is a response to the death of Eric Garner during an arrest for selling untaxed loose cigarettes in July 2014.

Such quality-of-life policing, the advocates claim, unfairly burdens minority communities and leads to such horrors as the Garner death.

But the NYPD’s public-order enforcement is driven by community demands — and it turns out that 911 and 311 calls complaining of disorderly conditions come overwhelmingly from minority neighborhoods.

Minimizing the consequences for lawless behavior would require ignoring the wishes of the very residents whom the advocates purport to represent.

Those law-abiding residents understand several things the council apparently does not: First, quality-of-life offenses not only make a neighborhood unlivable, they invite more serious crimes. And second, police are needed to fend off chaos in communities where family controls have broken down.

The accidental shooting death of Akai Gurley in the stairwell of an East New York housing project last November has led to increased calls to scale back police patrols in public housing.

Such patrols are said to target blacks and Hispanics, even though that is simply the demographics of public housing.

The police conduct so-called “vertical patrols” in housing stairwells and elevators because so many law-abiding tenants are victimized there.

To its discredit, the de Blasio administration settled a groundless lawsuit charging the police with discrimination in its public-housing enforcement, but the ongoing pressure against vertical patrols has only strengthened in the wake of the Gurley death.

The shooting death of Michael Brown in Ferguson, Mo., last August has prompted a nationwide movement to scale back penalties for ditching a court appearance and failing to pay criminal and traffic fines, though the shooting had nothing to do with those issues.

After the Justice Department eviscerated the lie that Officer Darren Wilson had gunned Brown down in cold blood while he was trying to surrender, Attorney General Eric Holder was determined to justify the Ferguson riots anyway.

He announced in March that black residents in Ferguson are oppressed by more generalized racism, emanating from allegedly draconian penalties for court delinquency and nonpayment of fines.

Any legal system must avoid penalizing people for being poor. But many municipal courts struggle with defendants who blow off their hearings and fees.

A black mayor of another small Missouri town defended his own town’s traffic and court fees to the New York Times in March: “Everyone’s saying, ‘Oh, no, that city’s just taking advantage of the poor.’ When did the poor get the right to commit crimes?”

Under the disparate-impact analysis of racism, however, being poor and black can work as a get-out-of-jail-free card.

Officer Michael Slager’s execution-style murder of Walter Scott in North Charleston, SC, this month appears to be a horrific act of police brutality.

But it’s being bootstrapped to argue against child-support enforcement in the case of poor, often minority, deadbeat dads.

After Slager stopped Scott for a traffic offense, Scott took off running because he owed $18,000 in child support payments and didn’t want to go to jail again. (Despite his child-support debt, Scott had recently purchased a used Mercedes.)

Slager must and will be brought to justice for the killing. But that abuse of force is no grounds for lessening fathers’ accountability for their children.

The criminal justice pendulum is swinging against personal responsibility and toward the use of race and poverty as an excuse for noncompliance with the law.

Perhaps the most egregious capitulation to lawlessness to date came Sunday, following smaller riots in Baltimore Saturday over Freddie Gray’s still-mysterious death.

Mayor Stephanie Rawlings-Blake said that Baltimore authorities gave space to those who wished to destroy. Her office later said she was misinterpreted and was not sanctioning violence. Monday’s vandals didn’t get the correction.

To be sure, reasonable accommodations should be made when a defendant makes a good-faith but ultimately unsuccessful effort to meet his court-imposed duties.

But in the long run, a two-tiered system of justice that winks at lawlessness when it is committed by officially favored victim groups will make life miserable for the millions of law-abiding residents of poor communities and erode the public-safety gains from proactive policing.

Heather MacDonald is the Thomas W. Smith fellow at the Manhattan Institute and author of “Are Cops Racist?”