Politicians, including the CHP, rallied behind the president after the coup attempt, but differences have since emerged over the scale of his crackdown. Mr. Erdogan has arrested some 50,000 people accused of links to the coup plotters, and has held a referendum that granted him greater powers, including over the judiciary.
In an interview with the German daily Die Zeit last week, Mr. Erdogan insisted that the judiciary in Turkey was independent and defended the widespread arrests, saying many of those detained, including journalists, faced serious charges of terrorism.
“If it turns out that they are innocent, the judiciary will release them,” he said. “But if they are guilty, the judiciary will rule accordingly.”
CHP organizers have urged marchers to react calmly to any provocation from pro-government opponents. Leaders commended the police management of the crowd on Saturday as exemplary.