Philadelphia is poised to become the largest U.S. city to decriminalize marijuana. Mayor Michael Nutter has pledged to sign a City Council bill imposing a $25 fine for possession of an ounce or less of pot. Those cited would reportedly have to appear before a judge, but would not have a criminal record. People caught smoking pot in public would face a $100 fine, which could be waived through community service. The measure could prevent thousands of arrests each year.