Turkey could just keep the Bosphorus closed to Russian shipping forever. That would probably make someone care.
'Forever' is a mighty long time.
No.... they cannot. Not by treaty, and not by force without a very big problem.
Russia would make Turkey care, intensely.
“Turkey could just keep the Bosphorus closed to Russian shipping forever. That would probably make someone care.”
There is a treaty that limits that somewhat.
But if Turkey did that, it would trigger the next modern war over the Black Sea (Ukraine and the annexation of Crimea being the first). Russia would not fare so well against Turkey as it has against Ukraine.
Turkey is getting pushy. The whole situation in Syria was Turk based and resulted in pushing the Russians out of Syria. Not a bad thing.
But closing the Bosphorus would cause a very serious war. Turkey is a NATO member and Russian aggression against Turkey would trigger Article 5. The US has nuclear arms based in Turkey, I believe.
So yes, Turkey should be taken very seriously.