Congress Tells Erdogan No on F-35s, a Test for NATO's Ankara

Introduction: a letter that lands right before the summit

A bipartisan reminder of the rules

Just days before the NATO summit set to take place in Ankara, a bipartisan group of American lawmakers chose this exact moment to send a clear signal to the White House: there is no question of letting Turkey back into the stealth fighter program for the F-35 as long as it keeps its Russian-made S-400 air defense systems. The letter, revealed on July 2, 2026, fits a pattern of congressional distrust toward Ankara that stretches back to 2019, the year Donald Trump himself excluded Turkey from the program after it bought those Russian missiles.

This is not a scheduling accident. The NATO summit in Ankara is meant to showcase the image of a Turkey that has become a reliable partner for the Atlantic Alliance again, at the very moment the Alliance is trying to demonstrate its unity against Russia. American lawmakers are making clear that this rehabilitation cannot come at any price, least of all the security of the West's most sensitive technologies.

Why this question resurfaces now

Federal U.S. law, through CAATSA (the Countering America's Adversaries Through Sanctions Act), imposes automatic sanctions on any country that buys major military equipment from Russia. Turkey purchased its S-400s in 2019, triggering its immediate expulsion from the F-35 consortium. Since then, Ankara has kept angling to rejoin the program, banking on its status as a key NATO military power and on the personal rapport between President Recep Tayyip Erdogan and Donald Trump.

But for the lawmakers who signed the letter, giving in now would send a very bad signal to every other ally that played by the rules. Allowing F-35 sales to a country that still hosts radars and Russian missiles theoretically capable of spying on the jet's stealth characteristics would mean torching decades of investment in that platform's security.

The symbolic weight of the Ankara summit

A showcase for Erdogan, a test for NATO

The choice of Ankara as this year's host city for the NATO summit is no accident. For Erdogan, it's a chance to present himself as an indispensable pivot for the Alliance, straddling Europe, the Middle East and the Black Sea. According to observers, the summit is expected to advance the debate on European defense spending, with Alliance officials floating an ambitious target of 5% of GDP by 2035.

Yet that same summit also has to grapple with the Turkish question, which has poisoned transatlantic relations for years. Defense analysts point out that this week amounts to a credibility test for NATO: can it demand major budget efforts from its European members while turning a blind eye to Ankara's shortcomings on shared security rules?

Defense spending, the new yardstick of loyalty

The U.S. Secretary of Defense has already warned that American financial contributions to NATO will now be tied to the spending efforts of other allies. This position, widely discussed ahead of the summit, illustrates the transactional philosophy of the Trump administration toward the Alliance: every ally must pay its fair share, or watch American commitment shrink.

In this context, the Turkish question becomes a textbook case: how do you reconcile firmness on security principles (exclusion as long as the S-400s remain in place) with the drive to strengthen collective deterrence against Moscow, where every ally counts, including Turkey with its second-largest NATO army by troop numbers?

The S-400 file, an open wound since 2019

Where the rift began

Rewind to 2019: under the first Trump administration, Turkey finalized its purchase of S-400 air defense systems from Russia, despite repeated warnings from Washington. The response was swift: exclusion from the F-35 program, CAATSA sanctions, and a freeze on deliveries of aircraft Ankara had already ordered. That decision, made under a Republican administration, shows that the hard line on this file has never been partisan.

Since then, Turkey has repeatedly tried to renegotiate its position, even offering to store the S-400s without activating them, or to transfer them to a third country. None of these proposals has convinced Washington, which demands a complete and verifiable disengagement.

The technological risk at the heart of the refusal

The technical argument remains central: S-400 radars could, in theory, pick up data on the F-35's stealth signature if they operate on the same territory. This risk of indirect espionage, even a partial one, is enough to justify the position of American lawmakers. The F-35 represents an investment of hundreds of billions of dollars for the entire Western consortium, and any technological leak to Moscow would be catastrophic for NATO's military edge.

The White House's ambiguous role

Trump, caught between public firmness and closeness with Erdogan

President Trump maintains a close personal relationship with Erdogan, whom he has often called a "strong" leader. That closeness feeds the worries of lawmakers, who fear the White House might buckle under Turkish pressure on the sidelines of the Ankara summit, in exchange for concessions on other regional files such as Syria or the fight against Kurdish armed groups.

Yet on the strictly military front, and on the deterrence posture toward Russia, the administration has broadly held a hard line through its Secretary of Defense, who has backed a general increase in defense spending across the Alliance. It's this duality that makes the Turkish file so delicate: it combines unpredictable personal diplomacy with structural military security demands.

Congress, guardian of the hard line

It is precisely because the executive branch can be volatile on this file that Congress chose to step in directly. The bipartisan letter notes that CAATSA is a law passed by both chambers, and that its enforcement should not hinge on the diplomatic whims of any given administration. It's a rare example of consensus between Republicans and Democrats in an otherwise deeply polarized Washington.

Industrial and allied stakes

The trust of F-35 partner nations

The F-35 program rests on a consortium of partner countries that collectively invested in its development: the United Kingdom, Italy, the Netherlands, Canada, Australia, Norway, Denmark, and several others. Readmitting Turkey without resolving the S-400 problem would send a signal of laxity to all these partners, who scrupulously respected American security requirements.

Defense industry players, including several major American names embedded in the F-35 supply chain, are also watching this file closely. A hasty decision could undermine allies' confidence in the long-term reliability of American commitments on military technology transfers.

The next-generation fighter, an additional argument

The signatory lawmakers also point to the development of the next-generation fighter recently announced by the American administration. Reintegrating Turkey into the F-35 ecosystem could complicate the protection of technological secrets surrounding this future aircraft, whose design partly builds on advances made with the F-35.

Russia's posture and the shadow of Putin over this file

Moscow, the silent winner of any eventual reintegration

If Turkey managed to keep its S-400s while regaining access to the F-35, it would amount to an indirect diplomatic victory for Vladimir Putin. The Kremlin has always sought to drive wedges within NATO, and Ankara's ambiguous relationship with Moscow, which has persisted despite the war in Ukraine, perfectly illustrates this strategy of division.

Turkey has kept diplomatic and commercial channels active with Russia throughout the Ukrainian conflict, positioning itself as an occasional mediator while continuing to sell drones to Kyiv. This balancing act makes the S-400 question all the more sensitive: accepting a compromise would mean rewarding this strategic ambiguity.

Ukraine, largely absent but still affected

Although this file may look purely bilateral between Washington and Ankara at first glance, it carries direct consequences for NATO's cohesion against Russia and therefore, indirectly, for support to Ukraine. An Alliance weakened by compromises on its own security rules would be less credible in its deterrence of Moscow, at a moment when Western unity remains the best weapon against the Kremlin's imperial ambitions.

What this file reveals about the state of the Alliance

A NATO of variable geometry

The Turkish case illustrates a broader reality: NATO sometimes struggles to enforce its own standards against strategically important members. Turkey, with its unique geographic position controlling access to the Black Sea, holds a negotiating leverage that few other members possess. That creates a permanent temptation toward differential treatment.

Still, defenders of the hard line note that it is precisely this rigor that has allowed the Alliance to maintain the trust of its members for decades. Giving in on this file would set a dangerous precedent for other allies tempted to flirt with Russian or Chinese suppliers.

European rearmament as backdrop

This debate unfolds against a broader backdrop of massive rearmament among European NATO countries, which increased their defense spending by tens of billions of dollars in real terms last year. This positive dynamic, welcomed by Alliance officials, shows Europe is finally taking the Russian threat seriously, which makes it all the more important not to undercut that momentum with poorly calibrated compromises on the Turkish file.

Possible scenarios going forward

An extended status quo

The most likely scenario, according to several defense analysts, remains the maintenance of the status quo: Turkey will continue to be excluded from the F-35 program until it verifiably gives up its S-400s. Unsatisfying as it is for Ankara, this status quo offers the advantage of predictability and avoids an open crisis within the Alliance just days before the summit.

In this scenario, Turkey could keep developing its own national fighter, the KAAN, as a partial alternative to the F-35, a strategy Ankara has already been actively pursuing for several years to reduce its dependence on Western technology.

A limited technical compromise

A second scenario, more optimistic for Ankara, would involve a technical compromise: verifiable deactivation of the S-400s, or their relocation outside Turkish territory under international supervision. This kind of arrangement has been floated before without ever succeeding, but pressure from the NATO summit could revive these discussions in the coming months.

The domestic American dimension of this file

A rare moment of bipartisan unity

In an American Congress often paralyzed by partisan divisions, this Turkish file stands as a notable exception. Republicans and Democrats agree on the need to keep pressure on Ankara, which reflects a shared conviction that national security must sometimes trump short-term political calculations.

This unity contrasts with other foreign policy files where partisan fault lines run much deeper, especially on questions that touch directly on the Trump administration and its personal diplomatic choices.

A signal sent to other capitals

Beyond Ankara, this file sends a message to other countries that might be tempted to play both sides on military procurement. India, for example, which also possesses Russian systems while seeking to strengthen its defense cooperation with the United States, is watching closely how Washington handles the Turkish case.

The impact on Western deterrence credibility

A question of strategic coherence

Western deterrence against Russia rests largely on the perception of coherence and NATO's determination. Every compromise perceived as weakness, even on a technical file like Turkish F-35s, can be read by the Kremlin as an exploitable sign of division.

This is why security experts insist on the importance of handling this file with the utmost rigor, regardless of short-term diplomatic pressures. The strength of the Atlantic Alliance lies in its ability to maintain uniform standards, even against powerful and strategically indispensable members.

The role of European allies in this debate

Several European NATO member states share American concerns about Turkey, particularly those with territorial or diplomatic disputes with Ankara, such as Greece or Cyprus. These countries are watching this file closely, as its outcome could influence their own bilateral relations with Turkey within the Alliance.

Lessons from recent history

The CAATSA sanctions precedent

The application of CAATSA sanctions against Turkey in 2019 remains, in the eyes of many experts, a relatively rare example of consistent enforcement of American law against an important strategic ally. This precedent is often cited as proof that the United States can maintain high standards even when the geopolitical stakes are complex.

This precedent today forms the legal and political basis on which lawmakers rely to justify keeping the hard line, seven years after the initial exclusion decision.

An administration that must pick a side

The Turkish file ultimately forces the Trump administration to choose between two sometimes contradictory logics: its preference for personal and transactional relations with strongmen like Erdogan, and its broader commitment to a coherent NATO rearmament against Russia. How it resolves this tension will say a lot about the priority it truly places on Western collective security.

Heading toward a tense summit in Ankara

What defense observers expect

Experts expect the F-35 file to come up behind the scenes at the summit, without necessarily producing major public announcements. Western diplomacies generally prefer to manage this type of dispute discreetly rather than turning it into a public friction point that could damage the image of unity the Alliance wants to project.

Nevertheless, the publication of the bipartisan letter right before the summit sends a strong signal both to the White House and to Ankara: Congress is watching this file closely and won't hesitate to intervene publicly if necessary.

A test of Western unity's solidity

Beyond the Turkish case, this summit will be scrutinized to assess NATO's ability to maintain its unity as President Trump's push for a fairer distribution of defense spending continues to test solidarity among allies. In this broader context, the Turkish F-35 file is just one piece of the puzzle, but a revealing one about the internal tensions the Alliance must manage.

The weight of Western defense industrials

A contested strategic market

Major American defense industrials are watching this file very closely, since it partly determines the confidence of future international customers in the F-35 program. Every partner country or potential client is watching how Washington handles security rule violations, which directly influences future purchasing decisions for Western military platforms.

Treatment perceived as too lenient toward Turkey could, paradoxically, discourage other potential clients from fully committing to the American ecosystem, fearing that the rules will be applied unevenly depending on the diplomatic interests of the moment.

European alternatives waiting in the wings

This context indirectly benefits competing European programs, such as the future Franco-German-Spanish combat aircraft or the British-Italian-Japanese program. These initiatives, which gain credibility as tensions around the F-35 persist, could benefit from any prolonged stiffening of relations between Washington and Ankara.

The Greek precedent and regional rivalries

Athens is watching this file closely

Greece, Turkey's historic rival in the Aegean Sea, is watching the F-35 file's evolution with particular attention. Athens has already joined the program and is receiving its first aircraft, a strategic advantage it obviously does not want to see diluted by a hasty reintegration of Ankara into the same military ecosystem.

Territorial tensions in the Aegean, never fully resolved, add another dimension to this file: a military rebalancing in Turkey's favor could revive bilateral friction that NATO would prefer to keep dormant, especially at a moment when Alliance unity is crucial against Russia.

Cyprus, another concerned party

Cyprus, a member of the European Union but not of NATO, is also watching this file with concern, given its own territorial dispute with Turkey since 1974. Any overly rapid military normalization between Washington and Ankara would be seen in Nicosia as a worrying signal about the hierarchy of Western priorities in the Mediterranean region.

Conclusion: firmness as the best guarantee of collective security

A file far from closed

The Turkish F-35 file perfectly illustrates the structural tensions running through NATO as it tries to reinvent itself against the Russian threat. Between the need to maintain rigorous security standards and the temptation to accommodate a strategically important ally, the Alliance will have to find a difficult balance in the months ahead.

The bipartisan letter from American lawmakers stands, in this respect, as a welcome reminder that national security rules should never be negotiable, even under the most insistent diplomatic pressure.

What this file says about the Alliance's future

As the Ankara summit opens amid historic European rearmament and growing firmness toward Moscow, how this file is handled will offer valuable insight into NATO's ability to reconcile internal cohesion with security demands against its adversaries. One thing is certain: Western unity remains, more than ever, the best weapon against Vladimir Putin's ambitions.

By Maxime Marquette, columnist

Columnist's transparency note

Who I am and my acknowledged biases

I sign my texts as a columnist and analyst, not as a neutral journalist. I defend a pro-Western, pro-Ukraine editorial line favorable to coherent NATO rearmament against Russia. On the Turkish file, I clearly lean toward maintaining the U.S. Congress's hard line, which colors my interpretation of the facts reported here.

What I don't know and my method

I have no access to internal White House discussions or to diplomatic negotiations that might be unfolding behind the scenes before the Ankara summit. My analysis relies exclusively on verifiable public sources: specialized defense press reports, official statements and public documents related to CAATSA sanctions. I invent no testimony and never claim to have had access to confidential information.

Sources

Primary sources

Newsmax, report on the bipartisan letter from U.S. lawmakers concerning Turkey and the F-35 — July 2, 2026

Anadolu Agency, factbox on NATO defense spending ahead of the Ankara summit

Secondary sources

Forbes, analysis of expected topics at the 2026 NATO summit — July 1, 2026

Wikipedia, entry on the 2026 NATO summit in Ankara

Reuters, aerospace and defense section

Independent analysis on Turkey's staging at the NATO summit

NATO, transcript of the press conference following defense ministers' meetings — June 18, 2026