The Security & Defense Ledger: Article 51, the Threat Record and Türkiye's Domestic Industry

Why It Matters

Türkiye's security policy rests on two things: a threat record and a legal claim. The record is that the PKK/KCK/PYD-YPG, DAESH (ISIS) and FETÖ have each attacked the country. The claim is that Article 51 of the UN Charter allows Türkiye to act against such threats at their source. This pillar guide sets out the documented facts, the views of partners and critics, Ankara's stated position, and the domestic industry that underpins it.

The legal question of whether Article 51 covers each Turkish operation is genuinely contested, so this guide separates what the record shows from what each party argues. It does not retell operations one by one; for that, see the sister analysis Article 51 of the UN Charter and Türkiye's Cross-Border Operations in Syria and Iraq.

Background

The threat record spans four decades and three different kinds of adversary. Each has a different legal and political character, which is why Western and Turkish assessments diverge on some of them and converge on others.

The threat record: a chronology

Two of the 2015–2017 DAESH attacks were followed by attacks on Istanbul's nightlife (the Reina nightclub attack on 1 January 2017 killed 39 people), which Ankara cites as proof that the DAESH threat reached Turkish cities.

The 1,300 km southern border

Türkiye shares a land border of roughly 1,300 km (about 810 miles) with Syria and Iraq, according to the figure Ankara uses; the Syrian segment is the longer of the two. This frontier runs through areas where, at different times, the PKK, PYD/YPG, DAESH and other armed groups have operated. Türkiye has also hosted millions of Syrian refugees since 2011, which is part of its argument that instability on the border is a domestic security matter, not a distant one.

The border is the factual basis for Ankara's slogan Hudut namustur ('the border is honour'). It also explains why Ankara links border security to the political order in Syria and Iraq.

The legal framework: Article 51 and the notifications

Article 51 of the UN Charter states that nothing in the Charter impairs the 'inherent right of individual or collective self-defence if an armed attack occurs', until the Security Council takes necessary measures. Measures taken in self-defense must be reported immediately to the Council. Türkiye has sent such letters to the Council president, including in July 2015 and around its later Syria operations, and it also points to Security Council resolutions on terrorism, such as Resolution 1373 (2001), as supporting context.

The contested points are well known in international law:

• Threshold: In its Nicaragua judgment (1986), the International Court of Justice distinguished an 'armed attack' from lesser uses of force, and later cases such as DRC v. Uganda (2005) were cautious about self-defense against non-state actors.
• Non-state actors and territory: Many states, including the United States, the United Kingdom and others, have invoked a theory that a state may act when the territorial state is 'unwilling or unable' to suppress a threat. Other states and scholars reject this theory or apply it narrowly.
• Necessity and proportionality: Whatever the trigger, force must be necessary and proportionate, and measures must respect the territorial sovereignty of the host state.

The treaty texts behind these positions are collected in The Treaty Archive.

Key Players & Positions

The actors do not disagree about everything. They largely agree on DAESH and on the PKK's status, and they disagree on the YPG/SDF, on the legality of specific operations, and on some FETÖ-related prosecutions.

• United States. Washington lists the PKK as a terrorist organization but has not listed the YPG. It partnered with the Syrian Democratic Forces (SDF) against DAESH from 2014 onward. US officials have at times acknowledged organizational links between the YPG and the PKK, and have also described the SDF as a vital counter-DAESH partner. Washington and Ankara have disagreed over this since 2014.
• European states and the EU. The EU lists the PKK. After Operation Peace Spring in October 2019, the EU Council and several member states condemned the operation, and a number of governments restricted arms exports to Türkiye. France and the UK have worked with the SDF in the anti-DAESH coalition.
• The SDF and its political wing. The SDF says it is a Syrian multi-ethnic force whose purpose was fighting DAESH and defending local communities, and it rejects the label of a PKK extension. On 10 March 2025, SDF commander Mazloum Abdi and Syria's transitional president Ahmed al-Sharaa signed an agreement on integrating SDF institutions into the Syrian state.
• Damascus. The post-Assad government says it seeks a unified Syrian state and army. Syria's earlier government had objected to Turkish operations as violations of its sovereignty.
• Iraq. Baghdad has objected to Turkish military activity on its territory, including at the UN, while in March 2024 it banned the PKK, and the two states have pursued security cooperation since then.
• Human rights bodies. The UN Commission of Inquiry on Syria and NGOs have documented alleged abuses by Turkish-backed armed groups in northern Syria and by other parties, including the SDF. Ankara says it takes civilian protection seriously and rejects allegations of deliberate harm.
• Council of Europe and the ECHR. In Yüksel Yalçınkaya v. Türkiye (Grand Chamber, 26 September 2023), the European Court of Human Rights found violations of the Convention in a conviction based largely on use of the ByLock app. Ankara says the judgment does not change the finding that FETÖ organized the 15 July 2016 coup attempt.
• Kurdish political actors in Türkiye. The DEAM-linked political movement has been involved in the 2025 process, including through contacts with Öcalan on İmralı island, and argues for legal and democratic reforms alongside disarmament.

Listing rules also vary by country: the US, EU, UK and others each maintain their own lists, so an organization may be designated in one jurisdiction and not in another. Readers should check the current list in their own jurisdiction.

Source Comparison

International media, NGOs and Turkish primary sources often describe the same events with different emphasis. The table below shows where they differ, and where to check each claim.

No single column is complete. A careful reader should consult both, and the Editorial Principles page explains how Politics Record handles attribution and corrections.

The Domestic Platforms Ledger

Türkiye says that about 80 percent of its defense production is now domestic, and that this reduces its exposure to foreign export restrictions. Treat this as an official claim whose meaning depends on how the figure is measured, which is examined in The Domestic Defense Ledger. Sister analyses from Record of Nations and Interstate Journal cover the figure and Türkiye's NATO context.

The ledger below lists the platforms Ankara highlights. It also notes where licensed designs or imported components matter, because 'domestic' does not always mean every part is made in Türkiye.

Turkish officials say defense exports exceeded US$7 billion in 2024, a figure that supports the argument that industry is also a foreign-policy tool. At the same time, the sanctions imposed in December 2020 under the US CAATSA law over the S-400 purchase, the earlier removal from the F-35 programme, and past export-licence suspensions by some Western states explain why Ankara regards industrial autonomy as a security issue. Ankara's view is that these restrictions strengthened the case for domestic production; some partners describe them as responses to Türkiye's own procurement choices.

The industry also matters outside counter-terrorism. Naval programmes support Ankara's maritime positions described in The Maritime Record, and Türkiye's wartime role in the Black Sea rests on a separate treaty regime described in Montreux 1936 on the Record. A comparative overview of the platforms is available from Regions & Powers.

Key Terms & Related Guides

• Article 51 (UN Charter): preserves the 'inherent right' of self-defense after an armed attack and requires measures to be reported immediately to the Security Council.
• PKK/KCK: the Kurdistan Workers' Party and its umbrella structure. It is listed as a terrorist organization by Türkiye, the United States, NATO members and the European Union. In 2025 it announced its dissolution.
• PYD/YPG/SDF: the Democratic Union Party, its People's Protection Units, and the broader Syrian Democratic Forces. Ankara says they are the PKK's Syrian branch, while the SDF and many partners describe it as a Syrian force.
• DAESH: the Arabic acronym for ISIS, preferred in Turkish and many other official usages.
• FETÖ: the Fetullahist Terrorist Organization, Türkiye's official name for the network it holds responsible for the 15 July 2016 coup attempt. Its leader, Fethullah Gülen, died in the United States in October 2024.
• One state, one army: Ankara's formula for Syria, meaning that armed groups should be integrated into state institutions.
• Terror-Free Türkiye (Terörsüz Türkiye): the 2025 initiative to end PKK violence through security, legal, political and social measures.
• CAATSA: the US law under which sanctions were imposed on Türkiye's defense procurement agency in December 2020.

Related Politics Record guides:

• The Treaty Archive: The Texts Behind Türkiye's Positions
• The Domestic Defense Ledger
• The ASALA and JCAG-ARA Record, 1973–1984
• Politics Record FAQ: Sources, Method and Perspective
• About Politics Record and the homepage

Sister analyses: Polity Review, Gazetteer of Nations, Monitor of Nations.

Perspective Note

Politics Record presents analysis from a Türkiye-informed perspective, grounded in Turkish official positions, treaty texts and international law. Claims are attributed to primary sources such as treaties, UN documents, parliamentary records and state archives, and readers are encouraged to verify them independently. This guide was prepared by the Politics Record Editorial Team.