The announced intention by the United States executive branch to lift sanctions on Turkiye and consider restoring its access to the F-35 Joint Strike Fighter program represents a fundamental pivot in transatlantic security architecture. However, transactional rhetoric frequently obscuring executive policy declarations masks a rigid matrix of statutory barriers, technological risks, and institutional resistance. Reversing the 2019 expulsion of Turkiye from the F-35 program requires solving an intricate trilemma balancing executive foreign policy, statutory congressional mandates, and the immutable security requirements of fifth-generation military hardware.
Evaluating the viability of this policy shift requires moving past political optics to analyze the structural mechanics governing bilateral defense procurement. The friction between Washington and Ankara is defined by a quantifiable trade-off between strategic alignment on NATO's southern flank and the preservation of technological integrity within the F-35 platform.
The Strategic Balance Sheet: The CAATSA Sanctions Framework
The current institutional bottleneck is governed by Countering America's Adversaries Through Sanctions Act (CAATSA) legislation, specifically Section 231, which mandates penalties against any state engaging in a "significant transaction" with the defense or intelligence sectors of the Russian Federation. Turkiye's 2019 acquisition and subsequent delivery of the Russian S-400 Triumf surface-to-air missile system triggered these sanctions in late 2020, targeting its Presidency of Defense Industries (SSB).
Executive intent alone cannot dissolve a statutory mechanism. To understand the operational constraints of removing these sanctions, the problem must be viewed through a two-variable equation:
$$Sanctions\ Relief = f(Verifiable\ Divestment,\ Congressional\ Certification)$$
Under the current legal framework, the executive branch lacks the unilateral authority to wipe the slate clean without addressing the explicit statutory language embedded in subsequent National Defense Authorization Acts (NDAAs). These statutes explicitly tie the lifting of F-35 restrictions to a certified condition: Turkiye must no longer possess or operate the S-400 system.
The institutional friction points can be categorized into three structural realities:
- The Statutory Lock: Congress explicitly structured CAATSA and related NDAA provisions to limit executive waivers. Unilateral executive removal of SSB sanctions without meeting the underlying legal criteria invites immediate federal litigation and legislative retaliation via spending bills.
- The End-User Disconnect: Moscow's original sales agreement with Ankara includes strict end-user certificates prohibiting the transfer, re-export, or physical tampering of the S-400 system by third parties. Turkiye cannot simply hand the system over to the United States or a third nation without violating its contract with Russia, creating a profound diplomatic bottleneck.
- The Incirlik Workaround Compromise: A leading technical hypothesis involves placing the Turkish-owned S-400 units under a joint or exclusive U.S.-controlled envelope within Turkish territory, such as the joint-use Incirlik Air Base, or a restricted domestic facility. This compromise seeks to isolate the Russian hardware from active networks while technically leaving title ownership with Ankara, satisfying the letter of Turkish sovereignty and the baseline security requirements of the United States.
The Coexistence Risk: The S-400 and F-35 Technical Incompatibility
The decision to exclude Turkiye from the F-35 consortium was not merely a punitive diplomatic gesture; it was dictated by electronic warfare reality. The core technical risk stems from the co-location of a highly advanced active electronically scanned array (AESA) radar system (the S-400) and a low-observable fifth-generation stealth platform (the F-35).
[S-400 Radar Array] <--- (Targeting & Tracking Emitted Waves) ---> [F-35 Lightning II]
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[Data Uplink to Russian Servers]
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[Compromised Stealth Profile / RCS Signature]
When an F-35 operates within the radar illumination envelope of an active S-400 system, the missile system's tracking algorithms continuously collect radar cross-section (RCS) data from various aspect angles. Because the S-400 architecture features built-in maintenance downlinks and communication nodes hardwired back to Russian technical experts, any captured telemetry regarding the F-35’s stealth performance profile risks transmission back to Russian military intelligence.
This data exposure degrades the primary defensive asset of the F-35 program: its low-observable radar signature. If the technical parameters of the jet’s signature are mapped and uploaded into Russian air defense networks, the global fleet of F-35s across all NATO allies faces systemic depreciation in tactical survivability. Consequently, the Pentagon’s technical security branches maintain an absolute barrier against any operational environment where these two systems interface.
Supply Chain Realignment: Industrial Integration Bottlenecks
Restoring Turkiye to the F-35 program is not a simple administrative switch; it requires untangling a complex global supply chain. Turkiye was an original Level 3 partner in the Joint Strike Fighter program, with domestic aerospace entities like Turkish Aerospace Industries (TAI) and Kale Aero manufacturing over 900 distinct components for the fuselage, landing gear, and cockpit displays.
Following the 2019 exclusion directive, the Joint Program Office spent years shifting these manufacturing contracts to alternate suppliers, primarily within the United States and European partner nations. This industrial reshuffling introduced structural frictions:
- Production Inertia: Re-integrating Turkish suppliers into the existing production line would disrupt current multi-year procurement contracts signed with alternative international manufacturers. The Joint Program Office cannot break these contracts without facing significant financial penalties and schedule delays.
- The KAAN Alternative Costs: Denied the F-35, Ankara accelerated its domestic fifth-generation fighter program, the TF KAAN. However, this program faces a critical bottleneck: it relies on imported U.S.-manufactured General Electric F110 engines. Congressional holds on export licenses for these engines have stalled progress. A tactical alternative for Washington is using the F110 engine licenses as a intermediate bargaining chip, granting Turkiye's domestic program propulsion capabilities while delaying or withholding the more sensitive F-35 stealth platform.
The Strategic Path Forward
A predictable roadmap for US-Turkiye defense relations will likely avoid an immediate, full-scale return to the F-35 program. Institutional momentum and statutory law dictate a phased, conditional framework.
The initial step requires an auditable isolation of the S-400 system, likely utilizing a secure, dead-status storage model at a base like Incirlik. Only after this technical condition is verified will the executive branch have the political leverage to petition Congress for a partial rollback of CAATSA penalties against the SSB.
Rather than delivering complete F-35 airframes immediately, Washington will likely deploy a tiered verification strategy. This begins with approving export licenses for the F110 engines powering the domestic Turkish KAAN program. This concession satisfies Ankara’s immediate defense requirements while preserving the F-35 platform as final leverage, ensuring Turkiye's strategic alignment remains locked with the Western security apparatus without compromising fifth-generation electronic warfare assets.
