Year 9 actually.
I fail to see any political or economic advantages in joining in the fight against ISIS as I am extremely wary that this will turn into the waste of time, money and manpower which was Afghanistan.
Well I can tell you one thing, Russia would certainly be fucked if IS is able to get a proper foothold in the region... This isn't just about the Mediterranean fleet and oil... If they (IS) are able to get a proper hold of the region, you will have a Sunni block that stretches from the southern Caucasus all the way to Yemen... That spells very, very bad news for Russia and its control over Chechnya, Abkhazia and Dagestan... In short, Russia could lose a bulk of the south which would fall into Sunni hands... There's a whole host of other reasons that it is beneficial for Russian involvement...
As for the West, well, Russophobia, fear of a imperialistic Iran, holding on to the hope that Turkey is a bone fide NATO member, protecting the status quo with the Saudis (ensuring the Saudi monarchy is in tact, because it is relatively benevolent to US and Israeli interests), etc are just some of the reasons that bring logic to much of what they are doing in the region at this moment of time...