Historic Breakthrough: US Signals Path for Turkey’s Re-Entry into F-35 Program as S-400 Obstacle Nears Resolution

(DEFENCE SECURITY ASIA) — A major realignment in NATO’s air-power architecture appears to be taking shape as new indications suggest Washington and Ankara are edging toward resolving one of the most contentious defence disputes of the past decade.

Reports now point to a breakthrough that could finally reopen Turkey’s pathway back into the F-35 Lightning II program, a development with vast implications for NATO’s fifth-generation capabilities and for the balance of air power from the Mediterranean to the Middle East.

The latest catalyst emerged when US Ambassador to Turkey Tom Barrack publicly acknowledged that Washington’s primary concern—Ankara’s ownership of the Russian-made S-400 air defence system—is “nearing resolution,” marking the first major signal of policy recalibration since Turkey was expelled from the program in 2019.

This shift comes amid intensifying geopolitical instability in both Europe and the Middle East, reinforcing NATO’s growing dependence on capable frontline states such as Turkey, whose geography and operational military footprint remain indispensable to Western strategic calculations.

Barrack, addressing a conference in Abu Dhabi, delivered the most concrete message yet regarding Ankara’s remedial actions on the S-400 issue.

“Turkey has resolved the ‘operability’ issues with its S-400 missile systems as they are not in use,” he stated, directly addressing the long-standing American concern that the Russian radar complex could expose F-35 stealth characteristics to Moscow.

Barrack then went further, affirming that Turkey is “moving closer to getting rid of the Russian system altogether,” and responded “yes” when pressed on whether Ankara had taken meaningful steps toward this outcome.

He added his belief that “those issues will be resolved in the next upcoming four to six months,” suggesting a defined timeline for a historic reconciliation.

If realised, this would mark Turkey’s re-entry into one of the world’s most technologically advanced and geopolitically influential fighter programs, an outcome that could reshape the future force structures of both NATO and Turkey’s air force.

How the S-400 Crisis Broke US-Turkey Defence Ties

The present moment is the culmination of an extraordinary policy rupture rooted in Turkey’s 2017 decision to acquire the S-400 Triumph air-defence system from Russia for approximately USD 2.5 billion (about RM 11.7 billion).

Ankara justified the purchase as a sovereign requirement after years of unsuccessful attempts to secure the US Patriot system and in response to expanding regional missile threats emerging from Syria.

However, Washington declared the S-400 acquisition a strategic breach of NATO security norms, arguing that operating Russian long-range radar in proximity to the F-35 could enable Moscow to map the aircraft’s radar-cross-section signatures, undermining the jet’s stealth advantage.

The US subsequently removed Turkey from the program in July 2019, halting deliveries, expelling Turkish pilots from Luke Air Force Base, and freezing its industrial participation.

Ankara had already invested USD 1.4 billion (RM 6.5 billion) in pre-payments for its initial order of up to 100 F-35A jets, a major financial and industrial loss compounded by the abrupt cancellation of long-term Turkish manufacturing contracts, including centre fuselage components and landing gear assemblies.

The fallout also triggered sanctions under the Countering America’s Adversaries Through Sanctions Act (CAATSA), marking the first time a NATO ally had been penalised under the US’s adversarial sanctions framework.

Yet throughout the crisis, Ankara insisted that the S-400 would not be integrated into NATO networks, with officials repeatedly stressing its “independent operational posture.”

Barrack’s confirmation that the batteries “are not in use” now reinforces this position and appears to satisfy Washington’s minimum threshold for re-engagement.

Why the F-35 and S-400 Cannot Coexist

At the heart of the dispute is a fundamental technological contradiction between a stealth aircraft designed to avoid radar and a radar ecosystem designed to detect it.

The F-35A Lightning II, powered by the Pratt & Whitney F135 engine generating 43,000 pounds of thrust, achieves speeds of Mach 1.6 and carries an internal and external weapons payload of 18,000 pounds, including precision-guided bombs, air-to-air missiles, and electronic warfare systems.

Its low observable design is supported by the AN/APG-81 AESA radar, sensor fusion architecture, and deep integration within NATO’s digital battlespace, enabling real-time data sharing and multi-domain operations.

Conversely, the S-400 Triumph fields the 91N6E Big Bird radar with detection ranges up to 600 km, alongside missiles such as the 40N6E with 400 km engagement ranges and speeds approaching Mach 14.

Its ability to track up to 80 targets simultaneously provides Russia with unmatched long-range situational awareness.

From Washington’s perspective, co-locating both systems risks exposing unique F-35 signatures—thermal, radar and electromagnetic—to Russian analysis, especially if the S-400 captures telemetry that could be transferred covertly or indirectly to Moscow.

The US insists that even a dormant S-400 poses a risk unless demonstrably inoperable or physically separated, which explains why Ambassador Barrack’s statement carries historic weight.

The technical incompatibility is magnified by the fact that Russian long-range tracking radars are designed to refine stealth detection algorithms over time, meaning even passive exposure to an F-35 could contribute incremental data that enhances Moscow’s counter-stealth network across Europe and the Middle East.

This risk becomes strategically intolerable for Washington because the F-35’s value does not lie solely in its airframe but in its role as a node in a classified, multinational information-sharing ecosystem whose integrity is compromised the moment adversarial sensors begin mapping its signature behaviour.

Moreover, integrating the F-35 into an environment containing active or dormant S-400 components creates a multi-domain vulnerability, as Russia has historically leveraged foreign-operated systems to support its electronic intelligence (ELINT) architecture, thereby blurring the line between sovereign defence assets and inadvertent data conduits for hostile actors.

A Decade of Negotiation, Retaliation, and Strategic Shifts

The road to the present breakthrough spans nearly eight years of escalating diplomatic tension that exposed the fragility of US-Turkey defence relations and revealed deeper structural conflicts within NATO’s evolving threat perceptions.

In 2017, Turkey formalised the S-400 agreement with Russia after Patriot negotiations failed to yield technology-transfer guarantees, underscoring Ankara’s broader strategic pivot toward defence autonomy and signalling its unwillingness to rely solely on Western procurement pipelines.

In 2018, the US Congress threatened program suspension as a deterrent, a warning realised in July 2019 when Turkey was officially expelled from the F-35 consortium, marking the most severe punitive action ever taken against a NATO member over procurement of a rival great-power weapon system.

In 2020, CAATSA sanctions were imposed, freezing military-industrial exchanges and choking high-technology cooperation, effectively severing decades of joint aerospace integration and signalling Washington’s determination to set a precedent for alliance discipline in the era of resurgent great-power competition.

Between 2021 and 2024, Washington maintained a rigid stance—no return to the F-35 unless Turkey divested the S-400 completely—reflecting US anxieties that even a dormant Russian long-range radar system could undermine the integrity of fifth-generation stealth networks across NATO’s southern and eastern frontiers.

Yet by 2025, the diplomatic climate shifted dramatically as geopolitical pressures mounted, with NATO recognising that alienating Turkey risked creating operational vacuums from the Eastern Mediterranean to the Black Sea at a moment when Russia and Iran were expanding their regional footprints.

The widening Middle East crisis, Russia’s ongoing conflict with Ukraine, and China’s expanding military presence in Asia have all sharpened NATO’s need for cohesive air-power integration, compelling Washington to reconsider punitive rigidity in favour of strategic reintegration of a frontline ally.

In September 2025, President Donald Trump and President Recep Tayyip Erdogan met in Washington, where discussions reportedly touched on a “creative resolution” to the S-400 impasse, signalling that political pragmatism had begun superseding earlier hardline doctrinal positions.

Trump later hinted Turkey was “going to do something for us,” suggesting Ankara had offered concessions that align with Washington’s long-term objective of preventing sensitive fifth-generation technology from being exposed to Russian intelligence ecosystems.

This context aligns precisely with Ambassador Barrack’s comments, which now consolidate the political and technical narrative: Turkey is moving toward de-facto disengagement from the S-400, creating a pathway that satisfies US security requirements while preserving Ankara’s strategic dignity.

Ankara’s push to classify the system as “inoperable” represents a strategic compromise, allowing Turkey to maintain formal possession while neutralising US fears by ensuring the system remains disconnected, unpowered, and operationally irrelevant in any scenario involving F-35 deployment or NATO network integration.

 The Turkish Perspective and Domestic Defence Implications

Turkish officials have long described the S-400 as a necessary shield against regional threats, particularly missile systems proliferating across Syria and the Eastern Mediterranean.

Yet they have simultaneously expressed an unambiguous desire to resolve the F-35 dispute.

President Erdogan reaffirmed this stance in October 2025, declaring: “I hope the F-35 issue will be resolved and CAATSA sanctions will be lifted.”

Turkish defence authorities have repeatedly warned that expulsion from the program damaged both its air-force readiness and its defence-industrial base, which had been tightly integrated into the multinational F-35 supply chain.

Ankara’s domestic fifth-generation program, the KAAN fighter, remains years away from frontline deployment, making the F-35 a complementary—not competing—capability.

For NATO, Turkey’s return could restore a critical southern air-power hub, supporting operations from the Black Sea to the Levant.

Yet resistance persists in the US Congress, where several lawmakers insist any F-35 transfer must be contingent on full divestment of the S-400.

Israel, too, has voiced concerns, fearing advanced stealth technology could be compromised in a region where Turkish foreign policy has diverged sharply from Israeli security interests.

If reinstated, Turkey is expected to pursue an initial request of 40 F-35A jets, a fleet that would significantly bolster its deterrence posture relative to Greece, which is already integrating the F-35 into its Hellenic Air Force inventory.

CONCLUSION

A major transformation in US-Turkey relations is now within reach as Washington acknowledges Turkey’s substantive steps toward neutralising the S-400 system and re-opening pathways back into the F-35 program.

With quotations preserved, timelines aligned, and strategic variables shifting, the coming months will determine whether Ankara’s long diplomatic effort finally bears fruit.

If successful, Turkey will rejoin the world’s most advanced fighter ecosystem, NATO will strengthen its southern air arc, and Russia will suffer a symbolic and material setback.

For Asia—particularly Malaysia and India—Ankara’s experience offers a blueprint for navigating the increasingly complex ecosystem of next-generation defence procurement under the shadow of great-power rivalry.

The countdown toward a historic reset has begun, and the global defence community will be watching whether Ankara seizes this moment to reclaim its place in the F-35 consortium and reshape NATO’s fifth-generation air-power balance for the decade ahead.

Turkey’s potential reintegration into the F-35 program would also restore crucial supply-chain interdependencies that previously linked Turkish industry to over 900 components of the aircraft, amplifying Ankara’s economic and technological footprint across the global aerospace sector.

Such a shift would simultaneously signal Washington’s recognition that Turkey’s geostrategic location—commanding the Black Sea, Mediterranean, and Middle Eastern corridors—remains indispensable to Western air and missile defence planning.

A renewed partnership would also accelerate Turkey’s doctrinal transition toward network-centric warfare, as the F-35’s sensor fusion and data-sharing capabilities would integrate seamlessly with NATO’s future joint all-domain command and control (JADC2) environment.

This re-entry would place pressure on regional competitors, particularly Greece, which had hoped its F-35 acquisition would create a decisive qualitative edge in the Aegean theatre.

It would also complicate Russia’s strategic calculus, as the loss of a NATO member operating the S-400 would weaken Moscow’s leverage and diminish the export credibility of its long-range air-defence portfolio.

For Middle Eastern militaries observing Turkey’s reorientation, this evolution reinforces the principle that successful fifth-generation integration requires not only technology but also political alignment, trust-building, and sustained adherence to alliance-based operational norms.

Ultimately, the trajectory of this diplomatic breakthrough will signal to global defence markets whether political disputes can be reversed through pragmatic military interoperability, or whether the S-400–F-35 controversy will remain a cautionary tale for states managing competing security partnerships. — DEFENCE SECURITY ASIA