The Turkish War of Independence against the occupying Allied Powers resulted in the abolition of the Sultanate on 1 November 1922, the signing of the Treaty of Lausanne (which superseded the Treaty of Sèvres) on 24 July 1923 and the proclamation of the Republic on 29 October 1923. With the reforms initiated by the country's first president, Mustafa Kemal Atatürk, Turkey became a secular, unitary and parliamentary republic. Turkey played a prominent role in the Korean War and joined NATO in 1952. The country endured several military coups in the latter half of the 20th century. The economy was liberalised in the 1980s, leading to stronger economic growth and political stability. The parliamentary republic was replaced with a presidential system by referendum in 2017. Since then, the new Turkish governmental system under president Recep Tayyip Erdoğan and his party, the AKP, has often been described as Islamist and authoritarian.