On Tuesday morning, Turkey downed a Russian SU-24 fighter jet on the grounds that it violated Turkish airspace while conducting an air operation against civilians in the Bayırbucak region in Syria. The downing came in accordance with Turkey's rules of engagement.A statement released by the Turkish General Staff said an unidentified fighter aircraft was warned 10 times in five minutes about an incursion into Turkish airspace at 9:20 a.m. According to the statement, two F-16's were deployed to shoot down the fighter jet after it failed to comply with the warnings. U.S. military officials also confirmed that Turkey repeatedly warned the violator Russian fighter jet before downing it.This is not the first time that Turkish airspace has been disturbed. Russia violated Turkish airspace for the first time while its forces were bombarding the Bayırbucak region in the Syrian town of Latakia and harassed Turkish F16's on Oct. 5. Following the incident, Ankara warned Moscow as part of the diplomatic framework and indicated that it would respond if the incursion continued. After this development, NATO sent strong messages to Russia about the violation. It is known that until this recent incident, Turkey had negotiated with Russia over the violation of airspace five times, and both countries agreed to avoid violating each other's sovereignty rights.Aside from all this, the rules of engagement, which entitle Turkey to protect its border with Syria, are very clear. After a Turkish F-4 fighter jet was downed by Syria in 2012, the rules of engagement between Turkey and Syria were amended. Accordingly, Turkey would strike any craft violating its airspace without warning. Based on this, a Syrian helicopter was shot down in 2013. This being the case, Turkey's attitude toward the recent incident has a legal ground that was overtly declared to Russia and the whole international community three years ago.Russia claims that it did not violate Turkish airspace. Of course, it is not possible for it to accept otherwise. Apart from its fighter jet's disruption of Turkish airspace, Russia has no legitimacy in its operation to bomb civilian areas. There is no evidence proving Russia's claims that there are terrorist elements in the region that it shells. Furthermore, it is no secret that throughout the Syrian civil war, Turkmens, who are being jointly attacked by Syrian President Bashar Assad's regime, Iran and Russia, have battled against terrorist elements like DAESH, the bombing of whom Russia has based the justification of its military presence in Syria.After the fighter craft was downed, Russia issued some scathing statements. Although these statements might have reassured the Russian public, they have no credibility in terms of international law.NATO, which convened to evaluate developments on Tuesday evening, is more cool-headed. After all, the organization has no other option other than siding with Turkey, its greatest ally in the Middle East. As a NATO member, the repulsion of the fighter jet goes beyond just a preference for Turkey. It is rather an obligation to interfere in border incursions, which came as a result of attempts to occupy an area because of its strategic importance and to gain strength during negotiations in the upcoming days. With this step, which was taken in accordance with international law, Turkey has sent significant messages to the region and world. The first one is that Turkey is resolute in protecting its national and regional security and interests.Unlike the Syrian regime, Turkey is not a country whose presence and legitimacy is in question. Unlike in the past, it is no longer possible for Turkey to stomach presumptuous attacks aimed at its presence in the level of international standing it currently resides in.Well, what will happen next? The answer to this question concerns the United Nations, which is in charge of protecting world peace. It should start to discuss Russia and Iran's illegal activities in Syria that threaten regional peace. It should not favor its permanent member, Russia, and give Turkey its due as a member that acts in accordance with the U.N.'s 51 articles that define the rules of use of force and the right to self-defense of its members.With this crisis, the whole world will once again test whether international law and civilians' right to life will be wasted by imperialist states.