Turkey, once an admired republic now in a state of transformation into something repugnant, just bought Russia’s advanced S-400 surface-to-air missiles. Reportedly, delivery of the first missile batteries is expected next year. What to make of this when it comes to international relations between Russia and the United States?

Good question. After all, Turkey is a NATO member — and NATO’s original purpose is to discourage Russian aggression.

Yes, Turkey has been a member of NATO the past six decades. Yet many global affairs analysts now ask: Does Turkey’s purchase of Russia’s surface-to-air missiles send a message to NATO that Turkey will oppose NATO policies when it comes to Ankara’s interests? The answer is evident.

A couple of years ago, Turkey tried to buy a similar system, only to retreat under pressure from the United States and condemnation from fellow NATO members. The United States objected because the system was to be sold through a state-run Chinese company. The United States had sanctioned that company for alleged missile sales to Iran. This time around, Turkey has moved forward with the purchase through a Russian arms export company.

So what’s behind Turkey’s decision to buy now? The partial answer is that Ankara realizes its ability to not only challenge the United States and NATO but to send a message that Ankara intends to play a pivotal role in its own regional affairs. Turkey is also upset about U.S. support for Kurdish militias in Syria, which Ankara perceives as a security threat, given its long history of conflict with the PKK (Kurdistan Workers Party). Turkey considers this occasional U.S. ally a terrorist group. This could well imperil Kurdish fighters, setting back the U.S.-led battle against Islamic State.

Security analysts also agree Turkey is humiliated by the European Union for its refusal to grant Ankara membership. Yet the EU bases its decision on Turkey’s human-rights abuses under controversial President Tayyip Erdogan: jailing journalists, limiting political parties’ membership and stifling freedom of expression, to name a few offenses.

The irony? Only a few years ago, Turkey was seen as a true secular model: a Muslim country with a democratic approach to governance. Gone are the days.

All of which brings us back to Turkey’s decision to purchase Russia’s advanced S-400 missiles. Make no mistake: This deal has its own challenges. The S-400 system is not built like NATO defense systems. Turkey will have to acquire considerable “know-how” to be able to copy and produce its own advanced system, something Russia is unwilling to share given the sensitivities of this particular technology. Moscow-based analyst Makienko argues: “For Turkey to be able to copy the S-400 system, it would have to spend billions to create a whole new industry.”

Of note: The sophistication of the S-400 lies in its ability to detect, track and then destroy aircraft, drones or missiles. It’s Russia’s most advanced integrated air-defense system and can hit targets as far as 250 miles away. Russia has also agreed to sell the system to China and India.

This deal has two outcomes. First, Turkey will emerge politically stronger, allowing it to influence the regional political landscape to its favor. Second, noting Turkey’s purchase, other countries in this volatile region and beyond will be eager to acquire similar technology from Russia, thus circumventing sanctions imposed by the West in response to Russia’s ruthless annexation of Crimea. Inevitable result: military buildup in a tense, wildly misunderstood stretch of the Middle East.

My conclusion: Along with Iran and Russia, Turkey will be stirring up the region. To some, my prediction may be preposterous; to those apprised of recent developments in the region, it should make sense. After the failed coup last year, Turkey embarked on an assertive foreign policy aimed at cementing its position as an influential regional player, pushing forward its agenda — whatever it may consist of.

One other thing: It became evident to Turkey a few years ago that neither the United States nor influential NATO members (Germany, France and Britain) take Ankara’s security concerns and economic interests seriously. As a result, Turkey has decided to go it alone, wooing Russia militarily and Iran economically.

Turkey’s policies are contrary to what Washington expects of an ally. The United States therefore must evaluate where it stands. Turkey is convinced it no longer needs to pursue a policy that fulfills Washington’s expectations but, rather, can forge one allowing it greater influence on its own terms. Turkey’s new direction reflects the will of its Muslim majority while being attentive to the geopolitical shift in the Middle East away from the West.

Veteran, global affairs analyst and educator David Oualaalou is author of “Volatile State: Iran in the Nuclear Age,” due for release in January. He lives in Hewitt.