The biggest danger from Russia is as an arms supplier. And for the most part everyone knows that.
On the NATO side, the usual suspects, which these days are the UK and France, are limping into a Syrian intervention. On the other side, Russia, which seemed at one point ready to abandon Assad is throwing more of its weight behind him.
The critics of inaction are right to point out that Putin has been emboldened by the mixed messaging in Western countries. A firmer trajectory would have probably kept Russia moving toward the exit. They are however wrong in assuming that this is proof that we should intervene.
Russia is a geopolitical enemy, but it's not such a grave foe these days that we ought to back even worse enemies in the name of dealing it a setback. The enemy of my enemy is my friend only when the enemy of my enemy isn't an even worse enemy of mine. And that's the case in Syria. Russia may be an enemy, but it's still largely in the nuisance category.
The biggest danger from Russia is as an arms supplier. And for the most part everyone knows that. The Soviet Army had two things going for it, numbers and nukes. Neither of these are nearly as much of a factor anymore.
The troublesome thing about Putin though is that engaging him in any way means being drawn into a competition whether you like it or not. Putin's entire public image was built on empty bravado. All those fake photos of him as the Great White Hunter were about selling an image.
Putin is a canny opponent and can and will back down if he senses that it's a no win scenario. But the sort of useless threats that modern nations specialize in these days only encourage him to taunt and threaten in order to claim victory.
In Syria, Putin now sees a chance to humiliate his geopolitical enemies by trumpeting that his horse is winning, even though he was about to abandon that horse a few months ago because he thought that he was going to lose. All the empty noise won't save the Russian economy, but it may add a useful political distraction.