NEW YORK (AP) -- In his nationwide effort for tighter gun control, Mayor Michael Bloomberg attributes historic crime lows in New York to strict gun laws that are strictly enforced. "If we are serious about protecting lives," he wrote in a recent newspaper editorial, "we have to get serious about enforcing our laws."
The National Rifle Association has dismissed Bloomberg's anti-gun campaign over the years as a publicity stunt and said last week that tighter laws would have no effect on public safety and crime.
But leading criminologists around the country say Bloomberg is right, for the most part. While acknowledging policing isn't the only factor in reducing gun violence, they cite the all-time low number of slayings in a city where most people are killed with guns.
"New York is showing the way for some good strategies in policing," said Harold Pollack, co-director of the University of Chicago Crime Lab.
Getting a thin layer of guns off the streets matters, said Franklin Zimring, author of "The City that Became Safe: New York's Lessons for Urban Crime and Its Control."
"Gun policing in New York got much more effective as every kind of street policing got more effective," he said.
Bloomberg is leading the charge but is backed by Mayors Against Illegal Guns, a coalition he started that now has more than 800 mayors from around the country.
"The more of us that we have together, the better we'll be able to make the case to Congress why sensible gun laws have to be on the books and have to be enforced," he said last week in Washington. "We just cannot continue to have 33 people a day killed in the United States with guns, and over 40 people commit suicide with guns every single day."
New York state had strict laws even before legislators passed the nation's toughest last week. And city regulations augment them. For example, in New York City, gun permits must be renewed every three years; there were no restrictions in other parts of the state until the new action. Obtaining a permit to carry a pistol or a revolver is incredibly difficult, and carrying a rifle or shotgun in the city is illegal. Out-of-state permits to carry a gun aren't recognized in the city.
At Bloomberg's urging in 2007, the state passed mandatory minimum sentencing laws for gun convictions. A city gun offender registry was created in which officers track serious gun convicts, not unlike sex offenders. Bloomberg fronted a sting operation to expose the gun show loophole.
But the laws didn't start working until police effectively started enforcing them, said Zimring, a law professor at the University of California, Berkeley.
Most of the murders in the city are committed with guns -- that hasn't changed. But policing has. Under Police Commissioner Raymond Kelly, "hot spots policing" proliferated, in which officers flood high-crime areas tracked by a computer reporting system. The department formed a firearms suppression unit in 2006 that identifies traffickers and uses undercover officers to buy and arrest them.
Crime has dropped almost across the board in the decade Bloomberg has been in office. There were 418 killings last year for a population of 8 million people, the lowest number since reliable records were kept starting in 1963. Chicago, for example, had 487 for 2 million people. In 1990, New York City had an all-time high of 2,245 killings.
"Is a lot of that effective street gun policing? Yes," Zimring said.
People caught violating the laws get punished, even famous people, like former New York Giants football star Plaxico Burress, who walked into a nightclub with a loaded gun tucked into his track pants in 2008 and accidentally shot himself in the thigh. The wide receiver had no criminal record but spent nearly two years in jail on a weapons charge.
"That's a deterrent," said Pollack of the crime lab. "You want to create a deterrent for carrying a gun, you prosecute someone who didn't injure anyone else. A celebrity, no less."
Most of the guns used in shootings in the city come from out of state, officials said. Overall, New York City has about 5,100 firearm-related arrests each year -- the majority of the 7,600 or so statewide, according to statistics from the state Division of Criminal Justice Services.
Those figures don't include when someone is arrested on a murder charge for shooting another person to death. A convicted gun trafficker was sentenced just last week in Manhattan to 15 years for selling 15 illegal guns to an undercover officer.
Mark Kleiman, a professor who studies crime policy at the University of California, Los Angeles, said that by enforcing laws, authorities in New York are keeping people off the streets who are more likely to be committing serious crime.
"There are clear consequences for having an illegal gun," he said.
But an NRA spokesman noted that crime has been dropping in many cities nationwide for decades, regardless of the gun laws.
"I think if you look at the overall violent crime rate that the FBI rate disseminates annually, it's been decreasing steadily nationwide over the last few decades," said spokesman Andrew Arulanandam. "And simultaneously, this is the narrative, the last few decades more people have been purchasing firearms."
And criminologists cautioned against giving the city and department too much credit -- other factors, such as the economy and education, play a role in the rise and fall of crime. Plus, nonviolent incidents like auto theft that don't involve guns at all are also down.
"Gun control has a mitigating effect on the crime rate, but you can't say it's one of the major factors; it's more complicated than that," said Jamie Chandler, a political science professor at Hunter College in New York.
Criminologists John Eterno and Eli Silverman argue in their book "The Crime Numbers Game" that crime statistics are manipulated. And before 2012, the number of gunshot victims remained relatively flat for the previous decade, hovering around 1,800 per year. It was about 1,600 last year, the lowest since comparable records started being kept in 1994.
"The murder rate goes down, and shootings are stable, so there is also a question of whether medical care has improved," said Jeffrey Fagan, a criminologist and law professor at Columbia University.
The mayor and police also cite "stop and frisk" as a deterrent -- in which officers stop, question and sometimes pat down people they think might be doing something criminal, even if the suspicions don't meet the probable-cause standard for an arrest.
After several lawsuits challenging the practice, a federal judge is now weighing whether remedies are needed to prevent unconstitutional "stop and frisk" encounters.
The stops have rocketed up on Bloomberg's 11-year watch, hitting a high of 684,330 last year. It nets 800 illegal guns per year, and generally only 10 percent of those stopped are arrested -- not enough to justify so many stops, some experts say.
"I endorse Bloomberg's campaign to end gun violence," Fagan said. "I just wish it were more successful than it is."