In the wake of the terrorist attacks in Brussels this week, senator and presidential candidate Ted Cruz called for increased law enforcement activity in American Muslim communities:

We must empower law enforcement to patrol and secure Muslim neighborhoods before they become radicalized.

Pressed to clarify his remarks, Sen. Cruz called for the resurrection and nationalization of a now-defunct NYPD surveillance program directed at the Muslim community in and around New York City. He argued that the “successful” program was shut down due to an excess of political correctness, leaving New Yorkers more vulnerable to the threat of terrorism.

The problem: even ignoring political correctness, the NYPD program was a failure by any reasonable standard.

In the aftermath of 9/11, the NYPD established a surveillance-based Demographics Unit. The goal of this unit was to “map” certain (almost entirely Muslim) communities in and around New York City, placing them under expansive police surveillance in order to sniff out would-be terrorists before they could launch attacks.

To achieve this mandate, the police infiltrated mosques, set up surveillance cameras around Muslim-owned businesses and residences, went undercover to monitor everyday conversations, and even infiltrated student groups at schools as far away as Yale and the University of Pennsylvania in order to monitor what students talked about, who they spoke to, and how often they prayed.

The end result of years of Demographic Unit surveillance on American Muslims was… nothing.

No convictions, no prosecutions, and, according to Assistant Chief Thomas Galati, not even a single legitimate lead.

That’s not to say there were never any terrorist threats in New York during this time period, only that the expansive “patrolling and securing” of Muslim neighborhoods failed to produce any actionable intelligence about them. A 2013 New York Magazine article contains an illustrative example:

In September 2009, the National Security Agency intercepted an e‑mail from a taxi driver named Najibullah Zazi to an e‑mail address linked to one of Al Qaeda’s most senior leaders. The message contained the line “the marriage is ready.”

Marriage and wedding were among Al Qaeda’s favorite code words for attacks, referring to the day that a suicide bomber met his brides, the maidens of the hereafter.

Trying to ascertain the scope of the plot, the NYPD searched the files of the Demographics Unit. Even though the rakers had canvassed Zazi’s neighborhood daily, and had even visited the travel agent where he bought his tickets between New York and Colorado, there was not a single piece of useful information. “There was nothing,” said [NYPD Lt. Hector] Berdecia.

In 2011, the Associated Press began publishing an in-depth exposé on the program, which spawned calls for reform and a wave of litigation against the city. By the time Bill de Blasio took office as mayor in 2014, the program had largely wound down, and the unit was eventually disbanded entirely.

There is little evidence that program made New Yorkers any safer. What the program undoubtedly did is cost millions of tax dollars and thousands of law enforcement man-hours that could have been spent investigating actual criminal behavior.

Sen. Cruz’s campaign also claimed that the end of the program made it more difficult for the NYPD to work with the Muslim community:

In New York City, Mayor de Blasio succumbed to unfounded criticisms and eliminated the efforts of law enforcement to work with Muslim communities to stop radical Islamic terrorism.

According to the NYPD itself and advocates within the New York Muslim community, the opposite is true. The NYPD program understandably alienated the local Muslim community and generated immense distrust between Muslim Americans and law enforcement.

While there is scant evidence that the NYPD program generated much in the way of actionable intelligence, it did generate civil rights and constitutional litigation against New York City. Several suits have been settled, with costs ranging in the millions of dollars.

Meanwhile, another suit in New Jersey remains on the docket. Last October, the Third Circuit Court of Appeals issued a strongly worded opinion reinstating a lawsuit against the NYPD surveillance program, invoking several of the darkest civil liberties violations in our history to explain why the suit should proceed:

No matter how tempting it might be to do otherwise, we must apply the same rigorous standards even where national security is at stake. We have learned from experience that it is often where the asserted interest appears most compelling that we must be most vigilant in protecting constitutional rights. “History teaches that grave threats to liberty often come in times of urgency, when constitutional rights seem too extravagant to endure.” …

Today it is acknowledged, for instance, that the F.D.R. Administration and military authorities infringed the constitutional rights of Japanese-Americans during World War II by placing them under curfew and removing them from their West Coast homes and into internment camps.

Yet when these citizens pleaded with the courts to uphold their constitutional rights, we passively accepted the Government’s representations that the use of such classifications was necessary to the national interest. … In doing so, we failed to recognize that the discriminatory treatment of approximately 120,000 persons of Japanese ancestry was fueled not by military necessity but unfounded fears. …

What occurs here in one guise is not new. We have been down similar roads before. Jewish-Americans during the Red Scare, African-Americans during the Civil Rights Movement, and Japanese-Americans during World War II are examples that readily spring to mind. We are left to wonder why we cannot see with foresight what we see so clearly with hindsight — that “loyalty is a matter of the heart and mind, not race, creed or color.”

Recycling failed, constitutionally-dubious policies is not a solution to terrorism, nor is singling out a largely law-abiding minority community for even more invasive government surveillance than it already endures. Police are already empowered to investigate criminal activity, and to patrol any neighborhood they like.

But the power to select entire neighborhoods or communities for intense police surveillance based solely on the ethnicity or religion is a power the police don’t need and shouldn’t have.