Soon after Syria downed a Turkish F-4 jet in 2012, Turkey announced to the world that it had instituted new military rules of engagement (MRoE) on the border with its southern neighbor. It had underlined its determination to strike at any violation of its airspace that emanated from Syria. A Syrian helicopter that tested the new move in 2013 was promptly shot down.Operating near the border, Russia recently began its own air offensive in support of the Assad regime and violated Turkish airspace twice early in October. However, Turkey chose not to put these new rules into effect, opting to warn Russia instead. Even U.S. Secretary of State John Kerry at the time shared his concern over the possibility of the repeat of such serious transgressions. The following days and weeks saw Turkish and Russian officials discuss how to avoid such incidents on five separate occasions. Each time, Russia was told that the rules of engagement would be implemented to the letter and warned about the deadly consequences repeating their actions. Russian officials said these were momentary lapses due to navigational errors and assured Turkey that they will be more careful in the future.Russia's decision to launch airstrikes in Syria in September sparked the tensest crisis with Western powers since the end of the Cold War. On Nov. 24, while Russia was once again raining bombs on anti-Assad opposition groups and Turkmen villages, two Russian fighter planes approached the border with Turkey, with one violating its airspace. According to a statement by the Turkish Armed Forces (TSK), the as of yet unidentified jet that violated the airspace was warned 10 times in five minutes, with each warning repeatedly ignored by the pilot. Then the F-16 fighter planes that were ordered into the air proceeded to strike the plane in accordance with the international accepted rules of aerial engagement.This, without doubt, is a serious crisis. This will definitely be a watershed moment in Turkish-Russian relations.Russia's total disregard of the international system was already apparent by the way it behaved in Ukraine and Crimea. Russia's acts were in total contravention to the accepted modes of international conduct and its repeated violations of the airspaces of NATO member countries places it at an international threat level at least equal to that of DAESH in the eyes of the West. A report by the European Leadership Network released in March this year showed Russian aircraft posed a threat scores of times to NATO armed forces and civilian flights in the English Channel, Baltic Sea, Black Sea and North Sea.Russia clearly poses a threat to the international system and, when one delves deeper, its conduct is no different from that of DAESH. Russian President Vladimir Putin now accuses Turkey of stabbing him in the back. Turkey has been observing Russia's actions in Syria since September with growing concern. Moscow's priority is not to fight DAESH but to prop up the Assad regime while securing its military installations in Latakia.Russia should stop trying to fool the international community by claiming to be fighting DAESH, and the international community, in turn, should stop being so gullible. Putin, in an effort to justify his ambitions in the Middle East to his people, is exploiting the tension and trying to portray Turkey as the aggressor. His aggressive efforts to broaden Russia's zone of influence over the energy transportation routes of the Middle East and energy supplies in the Eastern Mediterranean can be ascertained by just a quick look at what he has done.This growing threat from Russia should be dealt with by the U.S. and other NATO allies as a paramount security issue. Turkey is not alone in its concern over Russia's actions in the region. Saudi Arabia and Israel are also worried about the escalating Russian and Iranian involvement in Syria.NATO should continue to support Turkey's security establishment against any and all threats emanating from Syria. Russia is harming its own interests by losing a friend like Turkey, which is its largest commercial partner in the region. Moscow, which everyone knows is not above exploiting its energy riches as a ploy to dominate its neighbors, should be aware of the fact that it is losing the trust of its commercial partners as a secure energy source. Such acts will definitely push its trade partners to seek other avenues. Turkey thought the crisis in October had ended with a mutual understanding but Moscow's decision to take on Turkey means Russia is actually taking on NATO. Such a senseless escalation will push Moscow to the margins of the international community and will hurt its commercial and strategic interests.