The only reason Assad is talking trash right now is because of the Russians.
Before their intervention, he was slowly losing. The Syrian Army was having a hard time replacing their combat losses.
IMHO, he would have been forced to flee Damascus by now if it hadn’t been for the Russians.
He made a Faustian-like bargain with the devil (Russia) and soon he will have to repay the debt. Maybe he doesn’t care - as long as he gets to remain a figurehead leader of Syria.
And if Russia doesn’t demand repayment, the Iranians will.
True, before Russia helped , Assad was losing to the Islamic rebels. Of course, the only reason they were winning was support from Obama, Hillary and McCain. And the Saudis. So both sides have their backers
The US trained and supplied ISIS in Syria, so this was a fight between Russian puppets and American puppets since the git.