The Obama Administration is taking a side in the controversial NYPD stop-and-frisk trial. The Justice Department notified city officials on Wednesday that it is preparing a brief that will back the plaintiffs from the Center for Constitutional Rights, who argue that city police officers are stopping people based on their race. The move makes it more likely that the trial judge will appoint a federal monitor to oversee the department. Mayor Bloomberg’s expansion of the stop-and-frisk program resulted in 533,042 stops last year, 87 percent of them on blacks or Latinos. DOJ officials have until Thursday to file the brief.