The bill, sponsored by Kenney, was passed 13-3, enough to allow Council to override a veto. But the measure can't be made law until Nutter acts: He can sign it, veto it (forcing Council to vote once more ), or do nothing, allowing it to become law in September.
On June 20, Kenney, who is weighing a 2015 mayoral run, also publicly issued a letter to Nutter that urged him to approve the measure quickly.
Mark McDonald, the mayor's spokesman, pointed out Tuesday in an interview that Nutter has until Council's next session, scheduled for Sept. 11, to decide on the bill. "Its implications for the criminal justice system are under review," he said.
Kenney, a Democrat, has argued that the measure would help African American residents who have been penalized disproportionately. Last year, police arrested 4,336 people for marijuana possession, 83 percent of them black, according to Uniform Crime Reporting statistics for Pennsylvania.
Under Kenney's measure, people caught with 30 grams or less of marijuana - about an ounce - would be issued a citation and fined $25, but not arrested.
Nutter has noted that under state law, possessing any amount of pot is a crime. In June, Police Commissioner Charles H. Ramsey said state law trumps city ordinances. He said even if the bill becomes law, his officers will keep treating possession as a misdemeanor crime.
In Kenney's letter to Nutter, the at-large councilman repeated his argument that changing the law would "allow thousands of police hours to be better spent on preventing violent crime." He also credited Nutter with having "worked hard to shine a light on inequalities" that affect African American men, and suggested that signing the bill would advance that cause.
If the bill were made law, Philadelphia would join a rising number of state and local governments that have acted to significantly lessen penalties for possessing small amounts of marijuana.