Turkey has been forced to conduct its own counterterrorism operations in northern Syria and northern Iraq because the US has continuously disregarded its NATO ally's security concerns. In order to fight IS in the region, Washington has provided military training and support to the PKK and its Syrian affiliate, YPG, despite designating it a terrorist organization. Turkey has no choice but to escalate action to protect itself.
Turkey's obsession with Kurdish terrorism has dangerously escalated the situation in northern Syria, putting American forces at risk while also destabilizing the coalition's fragile control over IS. The SDF has no connection with the militant militia known as PKK and has been working with the US and coalition forces for years. This isn't what the US should expect from an ally and sets a dangerous precedent for other alliances.
There's a 93% chance that Turkey will be a NATO member continuously until January 1, 2025, according to the Metaculus prediction community.