How would turkey be ‘invading syria’ and Russia is not ‘invading Syria.’ Oh well, Russia is invited by one party. But we are going to tell Turkey they can’t defend their border? Do they get to tell us that?
Russia is in Syria at the request of the legal government. If Turkey goes into Syria, it's a direct invasion with no authority to be there.
They're going to protect their border by slaughtering Kurds. I hope if they cross into Syria they get crushed by Russia. Turkey has been supporting ISIS all along and has only bombed Kurds. To hell with them! Literally!
If Turkey wasn’t supporting al Qaida, their border with Syria wouldn’t be in turmoil. They have brought it upon themselves.
As far as invasions, Russia was invited by the only legitimate (however nasty it is) government of Syria.