Critics, including the White House, have said Comey doesn't have evidence, but it's pretty much impossible to gather such evidence, Kerik told "Newsmax Prime" host J.D. Hayworth.
Police will still respond to 911 calls, Kerik said, but won't engage in aggressive policing for fear of jeopardizing their careers.
Watch Newsmax TV on DirectTV Ch. 349, DISH Ch. 223 and Verizon FiOS Ch. 115. Get Newsmax TV on your cable system – Kerik said movie director Quentin Tarantino should apologize for calling police "murderers" at a recent rally. Police unions have called for a boycott of his films, including his current release, "The Hateful Eight."
The former commissioner also has been an advocate of prison sentencing reform, and said critics of President Barack Obama's have "jumped the gun."
The changes were made more than a year ago, he said, it is just now that some prisoners are beginning to be released.
The bigger issue is reform of the overall criminal justice system, Kerik said.
"Prison is an institutional learning center for thuggery and criminality, and we're taking first-time, nonviolent offenders, we're turning them into thugs and then we're sending them home," he said.