The political future of Turkish President Recep Tayyip Erdoğan’s main rival, İstanbul Mayor Ekrem İmamoğlu, has been thrown into jeopardy after his university diploma was annulled on Tuesday.  After winning the last three fiercely fought local elections for Turkey’s largest city — his opposition Republican People’s Party (CHP) overturning districts traditionally held by the ruling party in the latest 2023 race — the İstanbul mayor has emerged as one of the country’s most popular politicians and is seen as Erdoğan’s most serious challenger. Controversially, the decision regarding İmamoğlu’s diploma comes just days before he was expected to become the CHP’s presidential candidate at a March 23 party meeting. Many see it as a bid by Erdoğan to prevent İmamoğlu from running. The decision was taken by İstanbul University’s board of directors and has escalated a recent political dispute over the opposition politician’s academic credentials. Turkish law requires that presidential candidates hold a higher education degree. The ruling revoked the diplomas of 38 individuals, including İmamoğlu, citing “nullity” and “clear error” as the reasons for cancellation. Since taking office in 2019 İmamoğlu has faced multiple legal cases that had the potential to ban him from politics, including allegations of official misconduct, tender-rigging, bribery and threatening an official engaged in “fighting terrorism,” all levelled by government authorities. He has previously alleged that Erdoğan seeks to jail him for up to 25 years. İmamoğlu called the university’s decision “unlawful” in a post on X and vowed to continue his fight. “They do not have the authority to make such a decision. The authority lies solely with the Board of Directors of the Faculty of the School of Business. The days when those who made this decision will be held accountable before history and justice are near. The march of our nation, thirsty for justice, law and democracy, cannot be stopped. There is no salvation alone!” he posted. CHP Chairman Özgur Özel said the party would challenge the university’s decision in Turkey’s administrative courts. Imamoğlu had transferred to Istanbul University after attending Girne American University in North Cyprus in 1990. The mayor’s critics argue his previous university was not recognized by Turkey’s higher education council. Last month, meanwhile, Istanbul’s chief prosecutor’s office launched a probe into Imamoğlu on charges of forgery of an official document. İmamoğlu has argued that İstanbul University issued him an equivalency certificate, making his diploma legally valid.