The policy described in a memo dated Tuesday still offers plenty of exceptions: Only those with no criminal records, or minimal ones, qualify, and the cases of people caught smoking in public spaces — and especially around children — will not automatically be thrown out.
The district attorney, Kenneth P. Thompson, said in the memo that the policy was set up to keep nonviolent people, "and especially young people of color," out of the criminal justice system; an open case, Mr. Thompson wrote, can lead to problems with jobs, housing and school for defendants.
The policy became an early criminal justice policy test for Mayor Bill de Blasio, a fellow Democrat who had criticized police arrest practices over marijuana in terms similar to Mr. Thompson's. But in negotiating the policy, the mayor seemed to defer to his police commissioner, William J. Bratton, a proponent of the "broken-windows" approach to policing that holds that stopping lower-level crimes leads to stopping major crimes.
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