DIYARBAKIR, Turkey — “We don’t want Turkey to become Syria or Diyarbakir to become Aleppo.”

Those were the words of Tahir Elci, the president of the Diyarbakir Bar Association when I spoke to him after the recent Turkish election here in this troubled city of strong Kurdish national sentiment. On the night of the vote tires smoldered and the tear-gas-heavy air stung. In the center of the old city, rubble and walls pockmarked with bullet holes attest to the violence as police confront restive Kurds.

Elci was detained last month for a day and a half after saying in a television interview that the Kurdistan Workers Party, or P.K.K., was not a “terrorist organization” but “an armed political organization which has large local support.” An indictment has been brought against him that seeks a prison sentence of more than seven years. The P.K.K. is designated a terrorist organization by Turkey, the European Union and the United States.

“For a few words about the P.K.K., in which I said some of its operations were terrorist but it was not itself a terrorist organization, there is a lynching campaign against me,” Elci told me. “Yet there is no strategy among the Turkish security forces against the Islamic State, no real mobilization. If ISIS were treated like the P.K.K., it would be very different.”

As G-20 leaders prepare to gather in Turkey next week, the fissures in the fabric of a polarized society are more marked than at any time in the dozen years that President Recep Tayyip Erdogan has held power. His initial push, as prime minister, to oversee an era of neo-Ottoman opening both to Turkey’s neighbors and to minorities within the country, has collapsed in violence.