Any aggressive actions towards Turkey will be perceived as aggressive actions toward NATO
Previous incidents with Russian planes violating the airspace of various countries cannot be compared with what happened today with the Su-24, downed a Turkish aircraft.
Earlier, the Russian aircraft approached close to the airspace of other countries, but did not cross their border. Yes, it could provoke a dangerous incident as a result of maneuvering one of the parties, but, nevertheless, the grounds for the use of weapons was not.
Meanwhile, in Turkey, there has been a violation of the State border, and it was exactly as it should receive sovereign State was hit by an intruder. Before this incident has already been several violations of Turkish airspace by Russian planes and Russia warned of the possible consequences. But, unfortunately, the Russians it is ignored.
Turkey did so as to get a sovereign State
According to international rules, if the aircraft has on suspensions weapons it can fire. If such aircraft registered in the territory of a State should not be allowed to civilians dropped bomb. Turkey immediately announced that the plane was shot down by a fighter. It is said that it identified as "unidentified", that is, most likely, Russia has not been clearly identified. As it known in Syria Russians habitually postirali marking their aircraft.
This is a very serious incident. According to reports, one of the pilots was killed. I would not say that between the two countries necessarily war begins. However, much will depend on the design of the two sides, their willingness to admit their mistakes, to engage in dialogue, to express the arguments, etc. d. If it is proved that Russian aircraft crossed the border of Turkey, on the part of the RUSSIAN FEDERATION, it would be logical to admit his mistake. This would help to reach agreements on further easing the situation.
I think in this case, Russia will have to recognize that it has to do not with that opponent. Turkey is a NATO member, and any aggressive actions in her side will be considered as aggression toward the Alliance. So the stakes are raised very high.