ANKARA,— Turkey will need to rewrite its constitution to fully advance its peace efforts with the Kurdistan Workers’ Party (PKK), a senior adviser to President Recep Tayyip Erdogan said Monday. The government has been working to resolve a decades-long conflict with the PKK, which in May declared an end to its armed campaign. Two months after the announcement, PKK fighters began disarming, raising expectations of political and social reforms to expand rights for Turkey’s Kurdish population, which accounts for about 30% of the country. Mehmet Ucum, Erdogan’s chief adviser, told the news outlet HaberTurk that several of DEM’s proposals would require constitutional changes. Some political observers believe the government’s recent overtures, including indirect signals to PKK founder Abdullah Ocalan in prison, aim to secure Kurdish cooperation in return for reforms.