Washington Still Hesitates to Sell F-35s to S-400 Turkey

Introduction: a letter that reopens an old, explosive file

A bipartisan group that refuses to turn the page

A bipartisan group of American lawmakers has sent an official letter warning the Trump administration against any resumption of F-35 fighter jet sales to Turkey, citing persistent concerns tied to Ankara's possession of the Russian S-400 air defense system, according to reporting by The Jerusalem Post.

This letter does not appear out of nowhere: it fits within a long-standing parliamentary resistance to this deal, a resistance that refuses to fade despite repeated efforts by Ankara to convince Washington to reverse its exclusion from the F-35 program since 2019.

Why this story deserves to be told now

This missive, signed by lawmakers from both major American parties, explicitly cites statements attributed to Israeli Prime Minister Benjamin Netanyahu regarding the alleged intentions of Turkish President Recep Tayyip Erdogan, a detail that adds a delicate diplomatic dimension to an already sensitive file.

I am telling this story because it perfectly illustrates the permanent tension between commercial calculations, fragile military alliances, and legitimate strategic distrust that characterizes the complex relationship between Washington and a NATO partner as unpredictable as Erdogan's Turkey.

I will say it plainly: I fully understand the distrust of these American lawmakers. You do not gamble with the security of the West's most advanced military technology to satisfy the geopolitical whims of an ally as ambiguous as Erdogan.

And I insist on this: trust between allies is built on verifiable actions, not on simple diplomatic promises. Ankara must act first before demanding a return to the F-35 program.

The S-400, a bone of contention since 2019

An acquisition that cost Ankara dearly

Turkey's 2019 decision to acquire the Russian S-400 system immediately triggered Ankara's exclusion from the F-35 program, with Washington fearing that the simultaneous presence of this Russian system and the American stealth jet on Turkish soil would allow Moscow to gather sensitive data on the Western fighter's technological capabilities.

This exclusion marked a significant rupture in military relations between the two countries, with Turkey having invested considerable sums in the F-35 program before being cut out of it, a financial and strategic loss that Ankara has never fully accepted.

A decision with deep geopolitical roots

Turkey's choice of the S-400 over equivalent Western air defense systems already reflected, at the time, a troubling strategic drift by Erdogan toward closer ties with Moscow, despite Turkey's formal membership in the North Atlantic Treaty Organization.

This drift has never truly been corrected since, which explains why Washington's distrust of Ankara's real strategic intentions remains as sharp today, several years after the initial acquisition of the controversial Russian system.

Here is a perfect example of what I call Turkish strategic ambiguity: a NATO member on paper, yet close enough to Moscow to buy its most sensitive weapons systems. You cannot be halfway inside a collective security alliance.

The precise content of the bipartisan letter

Concerns expressed with firmness

According to The Jerusalem Post, the letter, jointly addressed to Secretary of State Marco Rubio and Secretary of Defense Pete Hegseth, expresses specific concerns about the risks that would come with resuming F-35 sales to Turkey as long as the S-400 system remains operational on Turkish territory.

The signatories of this letter stress that Turkey's position has fundamentally not changed since 2019, and that no credible guarantee has been provided by Ankara regarding the disarmament or permanent neutralization of the controversial Russian system.

An explicit reference to Netanyahu's remarks

A notable feature of this letter: it cites statements attributed to Prime Minister Benjamin Netanyahu expressing reservations about President Erdogan's long-term strategic intentions, a reference that shows how far this file extends beyond the strictly bilateral US-Turkish framework to touch the broader regional geopolitical balance.

This Israeli dimension adds an extra layer of complexity: Israel watches closely any evolution of Turkish military capabilities, given the recurring tensions between Ankara and Jerusalem on several sensitive regional issues.

I find it telling that even Netanyahu, usually cautious about publicly criticizing other regional leaders, voices such explicit reservations about Erdogan's intentions. That says a lot about the climate of distrust currently prevailing.

Turkey's Kaan ambitions and Trump's double game

A national Turkish fighter jet seeking American engines

Alongside this F-35 file, the Trump administration has reportedly been considering supplying American engines for the development of the Turkish national fighter jet Kaan, an ambitious Ankara project aimed at reducing its dependence on foreign military technology.

This decision appears contradictory to several American lawmakers, who struggle to understand why Washington would technically support the development of an autonomous Turkish fighter jet while maintaining a block on the direct sale of the F-35 to the same country.

An American strategy with multiple motivations

This apparent contradiction probably reflects a more nuanced Washington strategy: maintaining technological and commercial ties with Turkey's defense industry, while avoiding the transfer of the most sensitive and advanced technology represented by the F-35 as long as the S-400 question remains unresolved.

This two-speed approach illustrates how difficult it is for Washington to manage a relationship as ambivalent as the one with Turkey, a country strategically important to NATO but whose recent geopolitical choices inspire persistent distrust among many American lawmakers.

I see in this apparent contradiction further proof of the chronic unpredictability of the Trump administration on national security matters. A coherent line would nonetheless be necessary when facing a partner as slippery as Erdogan.

The congressional resolution to block the sale

A concrete legislative initiative

According to Turkish Minute, American lawmakers are preparing a formal resolution explicitly aimed at blocking any return of Turkey to the F-35 program, directly invoking the persistent threat posed by the S-400 system to the security of the West's most advanced military technology.

This legislative initiative, if it succeeds, would legally compel the Trump administration to maintain Turkey's exclusion, thereby limiting the White House's diplomatic room to maneuver on this sensitive file, regardless of whatever commercial or strategic pressure Ankara might apply.

A strong signal sent to Turkey

This parliamentary move sends a clear signal to Ankara: American distrust of Turkish strategic choices is not limited to a single administration but reflects a deeper bipartisan consensus within the US Congress on the security risks posed by continued possession of the S-400.

This rare bipartisan consensus, in today's polarized political climate in Washington, illustrates the scale of the security concerns shared by American lawmakers, regardless of party affiliation, on this specific strategic military file.

I welcome this rare bipartisan unity in Washington. When Democrats and Republicans agree on such a precise national security issue, it is generally the sign of a real danger rather than an artificial political quarrel.

Greece's position and regional tensions

Athens watches this file with concern

According to Parapolitika, American lawmakers of Greek origin have also voiced their opposition to any resumption of F-35 sales to Turkey, citing persistent tensions in the Aegean Sea and Turkish territorial claims that regularly worry Athens and Cyprus.

This Greek dimension of the file shows just how far the question of Turkish rearmament extends beyond the strictly bilateral US-Turkish issue to affect the broader strategic balance in the Eastern Mediterranean, a region where territorial tensions remain sharp among several NATO allies.

A fragile regional balance to preserve

Strengthening Turkish air capabilities without sufficient guarantees about its regional strategic intentions could destabilize an already precarious balance between Ankara, Athens, and Nicosia, three capitals whose relations remain marked by unresolved territorial disputes stretching back decades.

This complex geopolitical reality explains why many American lawmakers, beyond the sole question of the S-400, hesitate to further strengthen Turkish military capabilities without a prior clarification of Erdogan's regional intentions.

I often think of our Greek and Cypriot allies in this file, too often forgotten in the strictly US-Turkish analysis. Their security deserves to be fully factored into any Western strategic calculation on this subject.

Trump's ambiguous role in this saga

A personal relationship with Erdogan that complicates the calculus

President Trump has maintained a distinctive personal relationship with Erdogan for several years, a dynamic that sometimes complicates his administration's broader strategic calculations on this F-35 file, despite the reservations expressed by many members of Congress.

This personal relationship, combined with the potential commercial interests of an F-35 sale for the American defense industry, creates a constant tension between Trump's transactional impulses and the more structural security concerns raised by the American Congress.

Necessary firmness despite presidential unpredictability

I repeat here what I have said elsewhere: Trump remains an imperfect but broadly necessary ally for the West, on condition that his personal impulses never override the most fundamental national security imperatives, such as not transferring a technology as sensitive as the F-35 to a country still hosting a Russian defense system.

This bipartisan parliamentary resistance is precisely the kind of institutional safeguard needed to contain the riskiest impulses of the current administration on the most sensitive national security files.

Here I trust Congress more than the White House to maintain a coherent line of firmness toward Turkey. Democratic institutions must sometimes restrain a president's personal impulses, even a president I broadly support.

What Russia gains from this stalemate

An S-400 system that keeps serving Moscow's interests

Every day the S-400 system remains operational on Turkish soil represents, indirectly, a strategic success for Moscow, which has managed to embed Russian military technology at the heart of a NATO member country, creating a lasting crack in Western security architecture.

This situation perfectly illustrates Russia's long-term strategy of fragmenting Western unity through indirect means rather than direct military confrontation: selling weapons systems to NATO member countries to create dependencies and internal tensions within the alliance.

A lesson for the entire Atlantic Alliance

This Turkish file should serve as a lesson for all NATO member countries about the risks of dependence on Russian military technology, even for reasons initially presented as purely technical or budgetary by the governments involved.

Western vigilance must extend beyond the Turkish case alone to identify and correct any other similar vulnerability within the alliance, before Moscow can further exploit these gaps to weaken collective cohesion against its own geopolitical ambitions.

This is exactly the kind of structural vulnerability Putin loves to exploit. Every crack in NATO unity, however small it may appear, serves his long-term strategic interests against the entire West.

The economic stakes for American industry

A contract that would be worth billions

Beyond strategic considerations, this potential F-35 sale to Turkey would represent a substantial commercial contract for Lockheed Martin and the entire American industrial supply chain involved in producing this fifth-generation fighter jet.

This commercial dimension partly explains why certain American economic and political actors continue pushing for a swift resolution of this file, despite the legitimate security reservations expressed by many members of Congress.

A calculation that must never outweigh security

I firmly maintain that these commercial considerations, however legitimate for the American defense industry, should never take priority over the fundamental national security imperatives that justify maintaining Turkey's exclusion from the F-35 program.

Sacrificing the technological security of the entire Western alliance to satisfy short-term commercial interests would be a major strategic mistake, one whose consequences would far outweigh the immediate economic benefits of such a contract.

I say it again, forcefully: no commercial contract, however lucrative for the American defense industry, justifies compromising the collective technological security of the entire Atlantic Alliance.

Possible scenarios for the coming months

Between prolonged status quo and technical compromise

Several scenarios remain conceivable for how this file will evolve in the coming months: a continuation of the current status quo, a formal legislative resolution permanently blocking any resumption of the sale, or a technical compromise allowing a partial lifting of restrictions under strict independent verification conditions.

This last scenario, while theoretically possible, appears unlikely in the short term given the absence of clear signals from Ankara about its willingness to permanently neutralize the S-400 system, a precondition deemed essential by the majority of American lawmakers involved.

The importance of continued Western firmness

Regardless of which scenario materializes, this file illustrates the importance of continued Western firmness in the face of attempts to circumvent collective security rules, even when those attempts come from a formal NATO ally like Turkey.

This firmness must never be mistaken for hostility toward Ankara: it simply reflects a legitimate demand for strategic coherence necessary to preserve the technological and security integrity of the entire Atlantic alliance against Russian ambitions.

I close this section with a simple conviction: firmness toward Turkey on this specific file is not anti-Turkish sentiment, but a minimal requirement of security coherence within our Western alliance.

What this file reveals about NATO's internal fractures

An alliance that is never fully united

This F-35 file reveals a broader reality that many prefer to ignore: NATO is never a perfectly united and homogeneous alliance, but rather a coalition of countries with sometimes divergent interests, some of whose members maintain ambiguous relations with shared strategic adversaries like Russia.

This reality should not discourage us from recognizing the fundamental importance of the Atlantic alliance, but it should remind us of the need for constant vigilance to identify and correct internal weaknesses before they are exploited by determined external adversaries.

An opportunity to strengthen collective verification mechanisms

This Turkish file could serve as a catalyst for strengthening collective verification mechanisms within NATO, ensuring that any member country acquiring military technology potentially incompatible with Western security standards undergoes rigorous review before gaining any access to sensitive allied technologies.

Such a mechanism, if implemented consistently, would prevent future diplomatic deadlocks as prolonged as the one currently observed between Washington and Ankara over the F-35 and S-400 question.

Here is a concrete proposal I would like to see adopted by NATO: a systematic verification mechanism before any transfer of sensitive technology between allies, to avoid repeating the Turkish mistake with another member country in the future.

The precedent of CAATSA sanctions against Turkey

A historical reminder that still weighs today

It is worth recalling that Turkey's exclusion from the F-35 program in 2019 was accompanied by additional sanctions imposed under the CAATSA law, specifically targeting the Presidency of Defense Industries responsible for acquiring the S-400 system from Moscow.

These sanctions, among the harshest ever imposed on a NATO member, already demonstrated at the time the gravity with which Washington viewed this acquisition, a precedent that continues to weigh heavily on current negotiations over a possible resumption of F-35 sales.

A lesson Congress refuses to forget

This precedent largely explains why current American lawmakers categorically refuse to consider this matter closed or negotiable without a clear and verifiable resolution of the S-400 question by Ankara.

Congress's institutional memory on this file remains sharp: agreeing to resume the sale without sufficient guarantees would amount to symbolically erasing the gravity of the sanctions imposed in 2019, a signal that many lawmakers refuse to send to Ankara or to other allies tempted by similar acquisitions from Moscow.

I believe this CAATSA precedent must remain an example for any other NATO country tempted to flirt with Russian arms suppliers. Yesterday's firmness must continue to guide today's firmness.

The human dimension behind this geopolitical file

Turkish pilots deprived of a jet they had already come to know

Behind the cold geopolitical calculations lies a human reality too often overlooked: Turkish pilots had already begun their F-35 training before the 2019 exclusion, a human and professional investment brutally interrupted by Ankara's political decision to acquire the Russian system.

This human dimension of the file shows just how much geopolitical decisions made at the top of the state have concrete consequences for career military personnel who themselves have no direct influence over the strategic choices of their political leaders.

A Turkish defense industry also affected

Turkey's own defense industry suffered direct economic consequences from this exclusion, with several Turkish companies losing subcontracting deals tied to the F-35 program's supply chain after the 2019 American decision.

This economic reality adds further pressure on Ankara to resolve this file, beyond purely military strategic considerations, a pressure the Turkish government never fails to quietly raise during its diplomatic discussions with Washington.

I never forget this human dimension in my geopolitical analyses: Turkish service members acting in good faith are today paying the price of political decisions made by their leaders, a reality worth naming even though it changes nothing about the need for Western firmness.

The limits of our knowledge about Ankara's real intentions

An opacity that complicates any definitive analysis

An important methodological limitation must be acknowledged in this analysis: President Erdogan's real long-term strategic intentions regarding the S-400 system remain difficult to establish with absolute certainty, with Ankara alternating between contradictory signals depending on the interlocutor and diplomatic context.

This Turkish strategic opacity does not make it easy for Western analysts trying to assess whether Ankara's position stems from a purely temporary tactical calculation or from a more lasting geopolitical repositioning toward a Eurasian axis that includes Russia.

A necessary methodological caution

I prefer to acknowledge this uncertainty rather than categorically assert Turkish intentions that I cannot verify with sufficient certainty, while recognizing that Western strategic caution remains justified in the face of this persistent ambiguity.

This methodological caution changes nothing, however, about the documented factual reality: the S-400 system remains operational on Turkish soil, and this fact alone amply justifies maintaining the current restrictions on F-35 sales to Turkey.

I impose this rigor on myself deliberately, even though my personal convictions clearly lean toward distrust of Erdogan's long-term intentions on this specific file.

Conclusion: vigilance that must remain intact

A file far from resolved

This narrative of a bipartisan letter reviving American parliamentary opposition to the sale of F-35s to Turkey confirms that this file, open since 2019, remains far from resolved, and that distrust of Ankara's strategic intentions remains deeply rooted within the American Congress.

This parliamentary vigilance deserves to be praised as a positive example of democratic oversight over the most sensitive national security decisions, capable of withstanding commercial pressures and presidential personal impulses when fundamental strategic interests are at stake.

What to watch in the coming months

I will remain attentive to how this legislative resolution evolves and to any reactions from Ankara to this fresh demonstration of bipartisan resistance in Washington, a file that will likely continue to fuel diplomatic tensions between the two countries in the months ahead.

For the West as a whole, this Turkish file must serve as a constant reminder: the unity and strategic coherence of NATO demand unwavering vigilance against any attempt, even by an ally, to weaken the collective technological and security foundations of the Atlantic alliance.

By Maxime Marquette, columnist

Columnist's transparency note

Who I am and my acknowledged biases

I sign this narrative as a columnist-analyst for mad-m.ca, openly in favor of a firm Western line against any strategic ambiguity likely to indirectly benefit Russia. This editorial orientation does not prevent me from faithfully reporting the verifiable facts of this complex file.

I have no direct access to confidential diplomatic discussions between Washington and Ankara, and I rely entirely on established journalistic sources to build this analysis, rather than on privileged information I do not possess.

My limits and my commitment to rigor

President Erdogan's real long-term strategic intentions remain, as I have mentioned, difficult to establish with absolute certainty, and I commit to qualifying this analysis should new developments contradict the conclusions presented in this narrative.

I also commit to publicly correcting any factual error brought to my attention concerning the details of this bipartisan letter or any other element reported in this text.

Sources

Primary sources

Bipartisan letter warns Trump against F-35 sale to Turkey — The Jerusalem Post, June 28, 2026

US lawmakers raise concerns over Turkey F-35 deal — The Jerusalem Post, 2026

Secondary sources

Erdogan balances ties between Russia, Iran and the West — Newsmax, July 2, 2026

US lawmakers prepare resolution to block Turkey's F-35 return citing Russian S-400 system — Turkish Minute, June 29, 2026

Why is Trump sending American engines for the Turkish Kaan fighters while lawmakers block F-35s — Protothema, June 29, 2026

Greek-American lawmakers oppose Turkey's F-35 reinstatement — Parapolitika, June 27, 2026