ISTANBUL (AP) — Turkey has launched an air and ground campaign into Afrin, a Kurdish-controlled enclave in northwestern Syria. Codenamed "Operation Olive Branch," it's the latest chapter in a decades-long conflict between Turkey and Kurdish militants. Here's a look at why this is happening now and what's at stake: ___ WHAT'S THE GOAL? Turkish Prime Minister Binali Yildirim has said Turkey wants to create a 30-kilometer (20-mile) deep "secure zone" in Afrin.