They did it due to the drop in NYC's crime rate after adopting that policy. By the mid 00s, everyone was moving away from it due to over-policing, arresting innocent people, profiling, etc.
O'Malley employed those policies when he arrived as Mayor (999), but moved away from them for the reasons stated. The number of arrests dropped each year in Baltimore as did the crime rate.
By the end of his Mayoral term he had moved away from that policy and instead used a model called Citistat. It used community policing (cops asigned to certain neighborhood who got to know the residents and could tell where the problems were and targeted policing at know problem spots, such as drug markets.)
He did not employ those methods as Governor. Unlike say, Giuliani, O'Malley changed, evolved, and modified his approach until he got a fairer/more workable system.
From a 2010 article in the Baltimore Sun:
A lawsuit filed in 2006 on behalf of 14 people alleged that their arrests indicated a broad pattern of abuse in which thousands of people were routinely arrested without probable cause. The suit also alleged that the so-called "zero tolerance" system was endorsed and enforced by city officials under the tenure of then-mayor Martin O'Malley.
In a joint statement with the plaintiffs, the police department said it has agreed to institute policies that reject the "zero tolerance policing" and establish a range of appropriate officer responses to minor offenses. The department will issue written directives that spell out the elements of common minor offenses to ensure that officers are aware of the scope of their authority, and will train every officer on the new policies for offenses, the statement said.
Arrests in the city have fallen by the tens of thousands since O'Malley became governor, and the ACLU and NAACP said in the statement that they recognize that the current city leadership has taken steps to address the issue and "applaud those efforts."
What do community leaders in Baltimore think about O'Malley? From a recent Washington Post article:
“What was positive was that there was zero-tolerance for criminals and drug dealers locking down neighborhoods and taking neighborhoods hostage,” said the Rev. Franklin Madison Reid, a Baltimore pastor. “Does that mean there was no down side? No. But the bottom line was that the city was in a lot stronger position as a city after he became mayor.”
Benjamin T. Jealous, a former president of the national NAACP who worked with O’Malley when Maryland abolished the death penalty in 2013, credited him for supporting a civilian review board as mayor and for a sharp drop in police shootings that occurred during that time. Jealous said O’Malley’s “mass incarceration” police strategy is “a separate issue” than police brutality, and “a conversation for a different day.”“It was a period where a lot of mayors were doing whatever they could to try to reduce crime,” Jealous said.
O'Malley's statements on the issue:
Over the past year, as he has criss-crossed the country, O’Malley has talked about alleged police misconduct in places such as Ferguson, Mo. and North Charleston, S.C. On Saturday, he called Gray’s death “another awful and horrific loss of life.”
“Whether it’s a police custodial death or a police-involved shooting,” O’Malley said, “we all have a responsibility to ask whether there’s something we can do to prevent such a loss of life from happening in the future.”
Earlier this month, at a civil rights event convened by the Rev. Al Sharpton, O’Malley said his crime-reduction efforts as mayor saved many lives. “There are a thousand fewer black men in Baltimore who died violent deaths over the last 15 years than otherwise would have died had we not come together.”
FSogol (43,678 posts) 
22 replies
Every major city in this country followed that form of policing between 1990s and ealry 2000s.
