Turkey has a complicated political history but to color with a very broad brush, they were transformed from an Islamic state and former empire to a secular western aligned democracy by Kemal Ataturk. The Turkish army was politically aligned with Ataturk and would intervene to prevent Turkey from backsliding into an Islamic state. The current government executed a slow-rolling coup replacing military commanders and instituted a largely Islamic autocracy which for historical reasons remains a member of NATO but which would probably not join the alliance if the decision were to be made again today. They’re not a powerful nation militarily or economically by European standards, but seek to play both sides of international conflicts to magnify their influence. They cannot walk away from NATO without risking an existential threat from the military and economic fallout, but will get away with what they can.