When analyzing field indicators, it's easy to understand why Russia is the dominant force in northwest Syria both on the ground and in the air. Efforts led by Russia, with Iran and Turkey, to create a de-escalation zone around Idlib over the past year and a half have succeeded, despite minor differences of opinion.

But what happened June 18 definitely was a setback to Russia’s consolidation efforts in northwest Syria. For the first time ever, a Turkish military detachment of two armored personnel carriers and two mine-resistant ambush-protected vehicles displaying very visible Turkish flags patrolled along the Sajur River. The river, almost 15 miles from Manbij, constitutes a de facto boundary line between the Turkish military-backed Free Syrian Army (FSA) forces and the US-backed Syrian Democratic Forces.

That this patrol was supported by US Army helicopters was a totally new element. Although both the Turkish General Staff and the US military described the activity as "coordinated yet independent," it was obvious that this symbolic patrolling was a joint US-Turkish military effort, both in its planning and its execution.

Now there are two competing military activities occurring simultaneously in northwest Syria. One is the de-escalation effort by the Russia-Turkey-Iran bloc intensifying around Idlib, and the other is the US-Turkey deconfliction efforts focusing on Manbij.