The Workers' Party of Korea (WPK) is the sole ruling party of North Korea. Founded in 1949 from a merger between the Workers' Party of North Korea and the Workers' Party of South Korea, the WPK is the oldest active party in Korea. It also controls the Korean People's Army, North Korea's armed forces. The WPK is the largest party represented in the Supreme People's Assembly and coexists with two other legal parties that are completely subservient to the WPK and must accept the WPK's "leading role" as a condition of their existence. The WPK is banned in South Korea under the National Security Act and is sanctioned by the United Nations, the European Union, Australia, and the United States.
The North Korean Branch Bureau of the Communist Party of Korea (CPK) was founded in 1945. In 1946, it was briefly renamed to the Communist Party of North Korea, becoming independent of the CPK, and merged with the New People's Party of Korea in the same year to eventually form the Workers' Party of North Korea. In 1948, the WPNK founded North Korea. In 1949, WPNK merged with the Workers' Party of South Korea to form the Workers' Party of Korea. In 1950, WPK leader Kim Il Sung launched the Korean War, aiming to militarily unite Korea, but was deterred by American intervention. Kim Il Sung attempted to stay neutral during the Sino–Soviet split, while decreasing both Chinese and Soviet influence in the WPK. Kim Il Sung purged rival factions in the WPK in the 1950s and 1960s, while promoting his own cult of personality.