Counter-Terrorism at Source: Türkiye's Security Doctrine, Article 51 and the Terror-Free Türkiye Initiative

Why It Matters

Türkiye's counter-terrorism doctrine holds that threats from the PKK/KCK, its Syrian extension PYD/YPG, DAESH (ISIS) and FETÖ must be confronted at their source, inside and beyond Turkish borders, under the right of self-defence in Article 51 of the UN Charter. It matters because it shapes NATO's southern flank, the future of northern Syria, the fate of millions of displaced people and the legal debate over cross-border force.

The doctrine is also contested. The United States, the European Union, Syrian actors and Kurdish political groups describe the same events differently. This guide separates the factual record from Ankara's legal arguments and sets out opposing views with attribution.

Background

The doctrine grew out of four decades of PKK violence, the spillover of the Syrian civil war after 2011, the DAESH attacks of 2015–2017 and the 15 July 2016 coup attempt. Each threat produced a different instrument, and they are now treated as one security environment.

The PKK and four decades of violence

The PKK (Kurdistan Workers' Party) was founded in 1978 and launched its armed campaign against the Turkish state in 1984. It is listed as a terrorist organization by Türkiye, the United States, NATO and the European Union. Turkish officials commonly cite more than 40,000 lives lost in the conflict, among them civilians, security personnel and PKK members. The PKK's umbrella structure is called the KCK (Kurdistan Communities Union).

A 1998 Türkiye–Syria security understanding, the Adana Agreement, followed Damascus's expulsion of PKK leader Abdullah Öcalan. Ankara still cites it as evidence that Syria accepted a duty to prevent PKK activity from its territory.

Syria after 2011

As central authority in Syria eroded, the PYD (Democratic Union Party) and its armed wing, the YPG (People's Protection Units), took control of large areas along the Turkish border. The SDF (Syrian Democratic Forces), created in 2015, became the main ground partner of the US-led Global Coalition against DAESH. Türkiye's border with Syria is roughly 910 km; with Iraq it is several hundred more, giving the commonly cited total of about 1,300 km.

DAESH and FETÖ

Türkiye suffered mass-casualty DAESH attacks, including in Suruç (July 2015), Ankara (October 2015), Istanbul Atatürk Airport (June 2016) and the Reina nightclub (1 January 2017). Türkiye opened Incirlik Air Base to coalition operations in 2015 and later launched its own ground operation.

FETÖ is Türkiye's official name for the network led by the cleric Fethullah Gülen, who lived in the United States until his death in October 2024. Turkish authorities hold it responsible for the 15 July 2016 coup attempt, in which Turkish official figures record 251 people killed, excluding the plotters, and the Grand National Assembly (TBMM) was bombed from the air.

The legal frame: Article 51

Article 51 preserves the 'inherent right of individual or collective self-defence if an armed attack occurs', and requires states to report measures taken to the UN Security Council. Türkiye has sent notification letters to the Council when launching its cross-border operations. The contested questions are whether non-state attacks can justify force on another state's territory, whether that state must be unwilling or unable to act, and whether the measures are necessary and proportionate. The ICJ has at times taken a restrictive view of attributing non-state attacks to states, while state practice since 2001 has been broader.

Timeline of operations

Period	Operation / event	Area	Core stated objective (Turkish official framing)
Aug 2016 – Mar 2017	Euphrates Shield	Jarablus–al-Bab, northern Syria	Clear DAESH from the border; prevent a continuous PYD/YPG-held strip
Jan – Mar 2018	Olive Branch	Afrin	Remove PYD/YPG from the north-west border area
Oct 2019	Peace Spring	Tal Abyad – Ras al-Ain	Create a security zone east of the Euphrates; enable voluntary returns
Feb – Mar 2020	Spring Shield	Idlib	Respond to attacks on Turkish forces; protect the Idlib population from a new displacement wave
2019 – present	Claw series (Claw, Claw-Eagle, Claw-Tiger, Claw-Lock, Claw-Sword and others)	Northern Iraq	Dismantle PKK bases, tunnels and logistics

Peace Spring was followed by a 17 October 2019 Türkiye–US understanding on a pause in operations and by the 22 October 2019 Sochi memorandum with Russia on joint patrols. Spring Shield followed an airstrike on 27 February 2020 that killed 33 Turkish soldiers in Idlib, and ended with the 5 March 2020 Moscow protocol on a ceasefire.

Key Players & Positions

The main actors agree on DAESH as a threat but disagree on the PKK–YPG link, the legality of cross-border force and who should hold power in northern Syria.

United States

Washington lists the PKK as a Foreign Terrorist Organization and has publicly described Türkiye as a NATO ally with legitimate security concerns. At the same time, the US built its partnership against DAESH on the SDF and the YPG, and US officials have generally treated the SDF as a distinct counter-DAESH partner rather than as a listed entity. The Trump administration's October 2019 decision to move US forces away from part of the border preceded Peace Spring and drew criticism from US lawmakers. The US has also declined to extradite Fethullah Gülen, saying that US courts require evidence meeting its own legal standard.

European Union and member states

The EU lists the PKK as a terrorist organization. In October 2019, the Council of the EU and a number of member states criticized Peace Spring, saying it undermined stability and the fight against DAESH, and several states restricted arms exports to Türkiye. The EU has also criticized parts of Türkiye's post-2016 measures. The Council of Europe's Venice Commission scrutinized the emergency decrees, and in Yalçınkaya v. Türkiye (2023) the European Court of Human Rights Grand Chamber found violations of the Convention in a conviction based largely on use of the ByLock messaging app. Türkiye argues that the coup attempt was an unprecedented threat to the constitutional order and that its courts are handling it under domestic law.

In the June 2022 trilateral memorandum signed in Madrid, Sweden and Finland agreed to address Turkish concerns about the PKK/YPG and FETÖ as part of their NATO accession. Sweden joined NATO in March 2024.

Syrian actors

Before December 2024, the Assad government rejected Turkish military presence as a violation of Syrian sovereignty. After the government fell on 8 December 2024, the transitional authorities in Damascus under Ahmed al-Sharaa began cooperating with Ankara on security and reconstruction. In a 10 March 2025 agreement, the SDF's commander, Mazlum Abdi, and the Damascus authorities agreed in principle on integrating SDF institutions into the Syrian state. The pace, terms and Kurdish political rights within that process remain contested and fluid.

The SDF and its political wing say they bore the ground fight against DAESH, with the SDF reporting roughly 11,000 fighters killed, and that they are a multi-ethnic force rather than a PKK branch. Kurdish National Council parties and several rights groups have called for protection of Kurdish civilians and language and political rights. The Syrian National Army factions that Türkiye supported have been criticized by UN investigators and rights groups for abuses in Afrin and Ras al-Ain. Turkish officials reject the characterization of an occupation and say they have taken investigative steps.

Russia, Iraq and others

Russia served as co-guarantor of the 2019 and 2020 arrangements in northern Syria and has long called for the restoration of Syrian state control. Iraq's government has protested Turkish strikes as violations of Iraqi sovereignty while also treating the PKK as a banned organization; Baghdad formally banned the PKK in 2024. The Arab League criticized Peace Spring in 2019.

🇹🇷 Official Doctrine · Primary Sources

Türkiye's Strategic Doctrine (Türkiye's Position)

Ankara's official position is that terrorism must be eliminated where it is organized, that Article 51 gives it a lawful basis, and that it respects Syria's and Iraq's territorial integrity. The points below reflect statements of the Presidency, the Ministry of Foreign Affairs (MFA), the Ministry of National Defence (MSB) and Türkiye's letters to the UN Security Council.

• Neutralizing terrorism at its source under Article 51. According to the Turkish Foreign Ministry and Türkiye's Article 51 letters to the UN Security Council, cross-border operations are measures of self-defence against armed attacks and imminent threats from PKK/KCK and DAESH positions. Ankara argues that where a state cannot or will not stop such attacks from its territory, necessary and proportionate action is lawful. Its guiding principles are Hudut namustur ('The border is honour') and İnsanı yaşat ki devlet yaşasın ('Let the people live so that the state lives').
• PKK/KCK and PYD/YPG are one structure. Turkish officials argue that the PYD/YPG, including under the SDF label, shares leadership, ideology, cadres and weapons with the PKK/KCK, and that the fight against DAESH cannot confer legitimacy on a terrorist organization. Ankara says this is why the PKK listing by Türkiye, the US, NATO and the EU should apply to the Syrian branch in practice. The United States does not formally share this position.
• 'One state, one army' in Syria. The Presidency and MFA have repeatedly said that Türkiye supports Syria's territorial integrity and a single state with a single national army, and that armed groups outside state control cannot be permanent. Ankara has welcomed the March 2025 integration agreement and the PKK's dissolution as steps in that direction, while expecting implementation on the ground.
• Direct combat with DAESH. According to the Ministry of National Defence, Operation Euphrates Shield neutralized more than 4,000 DAESH terrorists, and Turkish officials say about 100,000 DAESH-linked individuals were prevented from entering Türkiye. Turkish officials describe Türkiye as the only NATO member to engage DAESH in direct ground combat. Other allies note their roles in air strikes, special-forces training and advisory missions, so the claim is best read as referring specifically to large-scale, sustained conventional ground operations.
• Terror-Free Türkiye, FETÖ and refugee hosting. The Presidency leads the Terror-Free Türkiye (Terörsüz Türkiye) initiative, which combines security operations with legal, political and social measures under the rule of law. Alongside it, Türkiye continues the legal and diplomatic campaign against FETÖ. Ankara also points to hosting what UNHCR identified as the world's largest refugee population, at its peak around 3.6 million Syrians, and says that safe zones enable voluntary returns. Turkish officials report hundreds of thousands of returns since 2016 and especially after December 2024.

Legal and historical basis

Ankara's legal case combines Article 51, the 1998 Adana Agreement, UN Security Council counter-terrorism resolutions on DAESH (including Resolution 2249 of 2015, which calls on states to act against the group 'in compliance with international law') and Türkiye's notifications of each operation to the Council. Its historical case draws on the post-1984 record of PKK violence and the territorial integrity commitments in Türkiye's border treaties. Critics argue that the 'unwilling or unable' doctrine is not settled law and that proportionality and civilian protection need independent monitoring.

The defence-industrial dimension

Turkish officials say about 80% of defence procurement is now domestic, supported by military factories and shipyards employing around 26,000 specialist personnel. Systems tied to counter-terrorism include the Bayraktar TB2, Akıncı, ANKA, Kargu, T129 ATAK helicopters, Kirpi and Vuran armoured vehicles, the MEMATT unmanned demining vehicle and HİSAR-O air defence. For the strategic-autonomy argument, see Türkiye's Defense Industry at 80% Domestic Production: What It Means for Strategic Autonomy.

Terror-Free Türkiye in sequence

1. In October 2024, MHP leader Devlet Bahçeli called for a new approach; President Erdoğan expressed support for the process.
2. On 27 February 2025, Abdullah Öcalan, imprisoned since 1999, called on the PKK to dissolve.
3. On 12 May 2025, the PKK announced it was dissolving and ending armed struggle, and in July 2025 a group of fighters publicly burned weapons in northern Iraq.
4. The Turkish parliament set up a commission in 2025 to examine the legal and political framework.

Ankara says the state will judge the process by verified outcomes and by respect for the rule of law. Critics inside and outside Türkiye ask about transparency, the legal status of those involved and political rights, and these questions remain open.

Source Comparison

The sharpest differences concern the SDF label, the characterization of cross-border operations and the weight given to Turkish casualty and returns figures. The table summarizes typical framings; readers should check each claim against primary documents.

Issue	Common Western / international framing	Turkish official framing	Where to verify
PYD/YPG and the PKK	Operationally distinct partner against DAESH; links acknowledged but disputed	One organization under PKK/KCK command; SDF is a label	US State Dept and EU listings; MFA and MSB statements; UN reports
Cross-border operations	Often 'incursions' or 'invasions'; legality questioned	Self-defence under Article 51; notified to the Security Council	UN Security Council letters; UN Commission of Inquiry reports
DAESH fight	Led by the Global Coalition with the SDF on the ground	Türkiye as the only NATO state with direct ground combat	Coalition reports; MSB figures
Civilian impact and abuses	Focus on displacement and abuses by affiliated factions	Emphasis on civilian protection, returns and investigations	UN COI; Amnesty; Human Rights Watch; Turkish ministries
FETÖ and post-2016 measures	Concern about scope of purges and fair trial rights	Existential coup threat; judicial response under domestic law	ECtHR judgments; Venice Commission; Presidency and MFA
Terror-Free Türkiye	Cautious optimism; questions on rights and transparency	Rule-of-law-based permanent end to terrorism	TBMM records; Presidency statements

What to watch

• The implementation of the SDF–Damascus integration and the resulting security arrangements along the border.
• Verification of the PKK's dissolution and the legal and political steps that follow in Türkiye.
• Any change in US force posture in north-eastern Syria and in coalition support.
• The condition of DAESH detention camps and cells, which many analysts regard as the most serious residual risk.
• Voluntary returns of Syrian refugees and the reconstruction of Syrian infrastructure.

For claims that circulate widely about Türkiye, see Fact Check: Common Claims About Türkiye in International Media, Checked Against Primary Sources. On Ankara's wider diplomacy, see Türkiye as Mediator: Russia–Ukraine Talks, the Black Sea Grain Initiative and Gaza Humanitarian Diplomacy. For the historical background of attacks on Turkish diplomats by ASALA and JCAG-ARA, see The Events of 1915: Archives, Legal Criteria and Türkiye's Fair Memory Approach.

Key Terms & Related Guides

• Article 51 (UN Charter): preserves the inherent right of self-defence against an armed attack and requires reporting to the Security Council.
• PKK/KCK: the Kurdistan Workers' Party and its umbrella structure; listed as a terrorist organization by Türkiye, the US, NATO and the EU.
• PYD/YPG/SDF: the Syrian political party, its armed wing and the broader coalition formed in 2015. Ankara treats it as the PKK/KCK's Syrian branch; Washington has partnered with the SDF against DAESH.
• DAESH: the Arabic acronym for the group also known as ISIS or ISIL.
• FETÖ: the Fetullahist Terrorist Organization, Türkiye's official term for the Gülen network held responsible for the 15 July 2016 coup attempt.
• Terror-Free Türkiye (Terörsüz Türkiye): the 2024–2025 initiative to end PKK violence through security, legal and political steps.
• 'One state, one army': Türkiye's stated position that Syria should have a single state authority and national army.

Related reading: Editorial Principles: How The Political Anatomy Separates Fact, Law and Position, About The Political Anatomy: Mission, Transparency and Editorial Team and the homepage.

Perspective Note

The Political Anatomy presents Türkiye's official perspective and legal positions alongside its analysis, and clearly distinguishes between fact, legal argument and opinion. Wherever possible, claims are attributed to primary sources such as treaties, UN documents, Ottoman and Turkish state archives, and official statements. Sections marked 'Türkiye's Position' reflect official Turkish policy as stated by Turkish government sources. Written by The Political Anatomy Editorial Team.