Turkey’s Innovation Party (YP) has filed a lawsuit seeking the annulment of a 2017 constitutional referendum that granted President Recep Tayyip Erdoğan sweeping powers by replacing the country’s parliamentary system of governance with an executive presidency, citing the use of unstamped ballots, the Euronews Turkish edition reported on Wednesday.
The party submitted its petition to the Ankara 1st Civil Court of First Instance, arguing that irregular ballots and envelopes tainted the legitimacy of the vote. Party Chairman Öztürk Yılmaz announced the move on social media, sharing court documents and stressing that the case was grounded in the allegation of widespread use of unstamped votes.
The unprecedented legal move comes against the backdrop of mounting judicial interventions into opposition politics. Opposition figures argue that a recent court ruling annulling the İstanbul provincial congress of the main opposition Republican People’s Party (CHP) has set a precedent for challenging past elections. Normally, Turkey’s Supreme Election Board (YSK) is the sole authority empowered to adjudicate disputes over elections. But with civil courts now asserting authority over party congresses, politicians say earlier nationwide contests could also be subjected to litigation.
Earlier this month former ruling Justice and Development Party (AKP) lawmaker Şamil Tayyar warned on social media that if civil courts start shaping electoral law, “legal security will be left unprotected and every election result could be put at risk.”
Referring to the 2017 referendum, he asked, “If tomorrow a civil court overturns the election board’s decision to accept unstamped ballots before the votes are even counted, what happens then?”
İstanbul’daki iptal kararının, Ankara’daki kurultay davasını kökten etkileyeceği aşikardır.
Bu silsile böyle devam ederse, Özel dönemi bitecektir.
Bu yorumu dün paylaşmıştım.
Sürece dair, kişisel kanaatimi belirtmek isterim.
Sorunun hem hukuki hem siyasi boyutu vardır.
Hukuk…
— Şamil Tayyar (@samiltayyar27) September 3, 2025
Nationalist opposition İYİ (Good) Party Deputy Chairman Hakan Şeref Olgun likewise called the İstanbul ruling an attempt to “engineer politics through the judiciary,” warning that it paves the way for contesting not only party congresses but also nationwide votes such as the 2017 referendum. He said his party was preparing to take the referendum to court.
Last week the İstanbul 45th Civil Court of First Instance annulled the CHP’s 2023 provincial congress, removed Chairman Özgür Çelik and 195 board members and appointed veteran politician Gürsel Tekin as interim leader. The crackdown comes less than a week before a high-stakes hearing in Ankara on September 15, where a civil court will resume a case seeking to annul the CHP’s November 2023 national congress that brought Özgür Özel to leadership. A ruling against the congress could strip Özel of his chairmanship, appoint a trustee to run the party or order a new congress.
The CHP, which won Turkey’s biggest cities in the 2024 local elections and is polling ahead of President Erdoğan’s ruling AKP, has faced intensifying legal pressure. At least 15 CHP mayors are currently in jail on corruption or terrorism-linked charges that rights groups say are politically motivated.
The 2017 constitutional referendum gave Erdoğan sweeping powers by changing the country’s system of governance to an executive presidency. At the time the CHP was called on to challenge the results on the grounds that Turkey’s top election authority had issued a controversial ruling on the day of the vote to accept ballots in envelopes not bearing official polling station stamps, but the party refrained from doing so. The Organization for Security and Co-operation in Europe (OSCE) report at the time criticized the YSK decision as “undermining an important safeguard and contradicting the law.” The decision raised concerns about the potential for ballot stuffing and undermined confidence in the results.