Well lets consider a few things. For one Russia had a lot less interest in stopping the Second Gulf War, or the Libyan action. In the case of Libya Russia essentially tacitly consented to it, by letting the Security Council resolution through. In this case Russia has a much greater interest in keeping the Assad regime in power. And has put in a lot of effort into making it happen. And of course the move to get rid of Syrian chemical weapons was well conceived and well executed. So can Russia stop the west? Yes. But only under certain circumstances. This may be one of those circumstances.
And of course this isn't over yet. Also as a minor technical note, Russia has naval facilities in Ukraine, Sevastopol, and in Abkhazia, at Ochamchira. Of course neither of those bases offer them the advantages that a Mediterranean base would. But lets not forget, Tartus housed a very small facility. Plans to expand it have been put on the back burner because of the civil war. I actually wouldn't be surprised if Russia re-opened a naval facility in Vietnam. It could resupply Pacific Fleet ships when they go to the Indian Ocean, and there was some mention of it in Russian press. Russia is also involved in a number of Vietnamese military infrastructure projects.
