Why Korea Is Divided: North Korea's History and How It's Ruled

From a colonial empire to two occupation zones

Korea’s division does not begin in 1950, with the first shots fired, but decades earlier. After the First Sino-Japanese War of 1894-95 and the Russo-Japanese War of 1904-05, Japan occupied the Korean peninsula; in 1910 it formally annexed it, ending centuries of Korean sovereignty over its own territory.

Japanese occupation ended with the Second World War: in August 1945, defeated, Japan laid down its arms and surrendered unconditionally to the Allied powers. That is where one of the century’s most debated decisions enters the picture. The task of figuring out how to handle the Japanese surrender on the Korean peninsula landed on two young officials at the US State Department, who picked the 38th parallel as the dividing line: north of it, Japanese troops would surrender to the Soviets, south of it, to the Americans. It was meant to be a temporary administrative and military split, not a permanent political border. Things turned out otherwise.

1948: two states are born

Over the following three years, the two occupation zones took opposite paths. In the north, the Soviets backed the rise of Kim Il Sung; in the south, the United States supported Syngman Rhee. In 1948 the temporary split hardened into something permanent: two separate states came into being.

In the north, Kim Il Sung quickly consolidated power and built an autocratic one-party regime under the Workers’ Party of Korea. It was the start of a system of government that, with internal changes, has lasted nearly eighty years.

The Korean War, and an armistice that never became peace

On 25 June 1950 Kim Il Sung’s army attacked South Korea, coming close to conquering the entire peninsula. US forces then led a UN-authorized operation to push the North Korean army back beyond the 38th parallel; by the end of 1950, after UN troops advanced toward the Chinese border, the People’s Republic of China entered the conflict as well.

A little over three years of fighting and parallel negotiations followed. After 158 negotiating meetings, on 27 July 1953 General William K. Harrison Jr., the delegate for the UN Command, and General Nam Il, the delegate for the North Korean army and Chinese People’s Volunteers, spent ten minutes signing eighteen official copies of the armistice agreement, drafted in three languages. The agreement took effect that same evening, at 10 p.m.

Practical example: the Korean armistice is like a match stopped by the referee’s whistle at halftime, never resumed and never closed with a final score. The players are still on the field, lined up in nearly the same positions as almost seventy years ago, waiting for a final whistle that has never come.

The agreement suspended hostilities and withdrew military forces from a strip about 4,000 meters wide, the demilitarized zone (DMZ); it established the Military Armistice Commission to oversee the truce; and it committed both sides to release and repatriate prisoners of war and displaced people. But the agreement’s text leaves no doubt that it was signed by military commanders, not governments, with no state signing it as a party. That is why North and South Korea remain, technically, in a suspended conflict more than seventy years on, with no treaty ever having closed it. That same year, the United States and South Korea also signed a mutual defense treaty, the legal basis, in effect since 1953, for the American military presence on the peninsula. After three years of war, the de facto borders ended up almost exactly where they had started, near the 38th parallel.

Who runs North Korea: party, dynasty, ideology

Since 1948, power in North Korea has passed, without interruption, through three generations of the same family: Kim Il Sung, then his son Kim Jong Il, then his grandson Kim Jong Un, head of state as president of the State Affairs Commission since 17 December 2011. Since 11 April 2019, the head of government has instead been Choe Ryong Hae, president of the Supreme People’s Assembly.

The decision-making center remains the Workers’ Party of Korea (WPK), whose Central Committee relies on three subordinate bodies: the Politburo, the Control Commission and the Executive Policy Bureau. Among its branches, the Organization Guidance Department and the Propaganda Department are considered among the most influential party agencies.

The relative weight of party and military, though, has not stayed constant. Under Kim Jong Il, the Songun doctrine, “military first,” took hold in the 1990s, raising the armed forces’ role in political life and in the allocation of resources. Kim Jong Un reversed that trend: he revived the Workers’ Party as the central political organ and pushed for tighter, more formal institutional control over the military, replacing three senior generals in 2018 to strengthen the party’s grip on the armed forces.

The guiding ideology, though, remains Juche, usually translated as “self-reliance”: a notion of independence and sovereignty that has dominated North Korean politics since the years after the Second World War. Three generations of the Kim family have ruled, since 1948, with near-absolute authority and heavy repression of dissent.

An isolated economy, hard to measure

North Korea publishes no reliable official economic statistics, so there is no nominal GDP figure declared by the state. The number most often cited by outside sources is a purchasing-power-parity estimate for 2023: about 15.416 billion dollars, or a GDP per capita of about 600 dollars. It should be treated for what it is, an external estimate, not an official figure from the regime.

The main productive sectors named by outside sources are military products, heavy machinery, electric power, chemicals, mining (coal, iron ore, limestone, magnesite, graphite, copper, zinc, lead and precious metals), metallurgy, textiles, food processing and tourism. Foreign trade, though, depends on almost a single partner: in 2023 China absorbed about 74% of North Korean exports and supplied about 97% of its imports, while every other trading partner remained marginal.

The estimated population in 2025 is about 26.4 million people, with a median age of 36.2 years and a life expectancy of 73.5 years, across a territory of 120,538 square kilometers. The armed forces count up to 1.3 million active-duty personnel, with compulsory service for men (ages 17-30) and women (ages 17-23), an obligation that sources put at up to ten years for men and seven for women. Between 2010 and 2020, military spending is estimated at 20% to 30% of North Korea’s GDP each year, an enormous share for any economy.

UN sanctions and relations with the outside world

Since 2006, North Korea’s nuclear and missile program has led the UN Security Council to adopt nine major resolutions, through 2017, nearly always in direct response to a test. Resolution 1718, from 14 October 2006, came just days after North Korea’s first nuclear test and banned transfers of heavy weapons and weapons-of-mass-destruction technology. Later resolutions followed each new test or missile launch, gradually widening the embargo: from a ban on exporting copper, nickel, silver and zinc (2016) to a full ban on textile exports (2017), to a cap on refined petroleum imports, limited to 500,000 barrels a year under resolution 2397 in December 2017.

The roots of this isolation reach back into the wider ideological standoff of the Cold War, which turned Korea into one of the grounds where the two superpowers fought each other by proxy, without ever clashing directly. That bloc logic, of opposing alliances and isolated economic systems, never fully lifted from the Korean peninsula: it has stayed frozen, together with the 1953 armistice, along a border that, as of 2026, no treaty has yet made permanent.