FILE PHOTO: Parts of a Russian S-400 defense system are unloaded from a Russian plane at Murted Airport near Ankara Reuters

Turkey conducted its first test of its Russian-made S-400 at the end of November, flouting NATO’s admonishments about the air-defense system just days before a summit of the alliance’s leaders.

The S-400 system isn’t operational yet, but the saga around it and Ankara’s other activities present real and ongoing challenges to NATO, despite the alliance’s leaders‘ attempts to play down growing rifts.

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After months of warnings from the US and other NATO members, Turkey tested its S-400s last week, putting the Russian-made air-defense system, deployed to an airbase near Ankara, up against US-made F-16 jets.

The S-400 was delivered to Turkey this summer but hasn’t become operational, which Ankara has said will happen in April.

But the system has been a point of contention since before it arrived in Turkey, and despite NATO leaders‘ assertions otherwise, the S-400 is one of many issues casting a pall over the alliance as it turns 70 years old.

‚We are talking about it constantly‘

FILE PHOTO: S-400 surface-to-air missile system after its deployment near Kaliningrad Reuters

NATO is concerned about the S-400’s potential to hinder interoperability among its forces, though Turkey says the S-400 will not be integrated with NATO systems. The US is especially worried about its potential to compromise technology on the F-35 stealth fighter. It has already kicked Turkey out of the F-35 program.

The US also continues to threaten Turkey with sanctions over the S-400 — lawmakers from both parties, angered by Turkey’s incursion in Syria, have called on Trump to impose them.

US officials have often paired criticism of Turkey for the purchase with optimism that the dispute can be resolved.

„Turkey’s acquisition of sophisticated Russian military equipment, such as the S-400, creates some very serious challenges for us, and we are talking about it constantly,“ President Donald Trump said after a meeting with Turkish President Recep Tayyip Erdogan at the White House on November 13.

„We talked about it today. We’re talking about it in the future. Hopefully, we’ll be able to resolve that situation,“ Trump added. „We’ve asked our secretary of state and minister of foreign affairs and our respective national security advisers to immediately work on resolving the S-400 issue.“

Turkey\'s President Tayyip Erdogan listens as he meets with U.S. President Donald Trump in the Oval Office of the White House in Washington, U.S., November 13, 2019 Reuters/Tom Brenner

Asked last week about Turkey’s November 26 tests, Secretary of State Mike Pompeo said it was „concerning“ but that the US was still „hopeful.“

„We’re still talking to the Turks. We’re still trying to figure our way through this thing,“ Pompeo added, saying the US „made very clear to the Turkish government our desire to see them move away from … putting into full operationalization the S-400.“

The current US proposal would have „Turkey lock up the S-400 systems in storage, not use them, and allow American technicians to occasionally visit and ensure that they’re not being used,“ Omar Lamrani, senior military analyst at geopolitical analysis firm Stratfor, told Business Insider the day after Trump and Erdogan’s meeting.

„If Turkey does that, then the US would accept the sale of F-35s, and they can get the ball rolling in terms of getting that relationship back on track, sell Patriot missiles as a replacement, etc.“

Turkey is unlikely to go for that.

„They see it as how are they going to explain to their people, for instance, that, ‚Hey, we bought this S-400 system for billions of dollars and now we’re just going to lock them up in storage for no use,'“ Lamrani said. „It’s a hard sell for Ankara.“

Erdogan has said he’s open to buying the US-made Patriot air-defense system, which Trump continues to offer, but described „the proposal to completely remove the S-400s“ as „meddling in our sovereign rights.“

First parts of a Russian S-400 missile defense system are unloaded from a Russian plane at Murted Airport near Ankara Reuters

Turkey’s purchase of a second S-400 system has been delayed for what Ankara describes as technical reasons, which may be an effort to keep open room for negotiation, Lamrani said, though Turkish officials expect a deal „before too long,“ according to Russian media.

Turkey may be angling for some sort of agreement on the S-400, but what that would entail, if it’s even possible, is unclear, according to Rachel Rizzo, an adjunct fellow at the Center for a New American Security and a fellow at Robert Bosch Stiftung, a German non-profit research foundation.

„It’s highly unlikely that Turkey will abandon its plans to activate the S-400 system in April, especially given that it tested the system only last week,“ Rizzo said. „Instead, it will try to find some middle ground with the goal of staving off Western sanctions. Unfortunately, that middle ground seems difficult to find at the moment.“

‚A thorn in everyone’s side‘

Like their political counterparts, NATO military leaders continue to emphasize their good relationship with Turkey.

„Military-to-military relations with Turkey remain extremely strong, and they are very important,“ Air Chief Marshal Sir Stuart Peach of the UK’s Royal Air Force, head of NATO’s Military Committee, told reporters in Washington in November.

„I continue to enjoy a strong relationship with the Turkish chief of defense and with Turkish military authorities, and we continue to welcome and thank Turkey for their continued support for many NATO commissions, activities, and operations,“ Peach said.

NATO continues to operate early-warning aircraft from forward bases in Turkey, Peach added, and the US continues to operate out of Incirlik air base, where a joint US-Turkish team recently carried out inspections.

„Of course, procurement is a sovereign choice,“ Peach said when asked about the S-400. „What NATO has done throughout its history is make clear that we are focused on interoperability between allies, therefore equipment has to be interoperable.“

putin erdogan Osman Orsal/Reuters

Comments like Peach’s are to be expected from NATO military officials. „They have to say that and they want to say that, because they want to maintain that relationship. But underneath that, clearly there are issues,“ Lamrani said.

It’s not the first time the NATO has butted heads with one of its members, nor is it surprising that Turkey is at odds with the rest of the alliance, given its position between east and west, Rizzo said Monday.

„There’s no question that Turkey is causing problems for NATO. It’s seen as both strategically important but also as a thorn in everyone’s side,“ Rizzo said, pointing to the S-400 issue, as well as the Syria incursion and general democratic backsliding.

The NATO Leaders Summit in London on December 3 and 4 may end with a group photo and positive statements, but those gestures are increasingly unable to mask fissures within the alliance.

„There’s no NATO mechanism for punishing Turkey (or any other member for that matter) for actions that it takes, so it will be up to individual members to find other ways to pressure Turkey to bring it back in line,“ Rizzo said. „I don’t see the issues with Turkey being solved any time soon. They’ll continue to pose strategic challenges and upset alliance cohesiveness, which is probably the most damaging side effect of its various activities.“