One barrier to reconciliation among the people who live on the Korean Peninsula is not necessarily a disagreement on economic philosophy or the demilitarized zone, but the Christian church.

Christianity has played a significant role in Korea since Protestant missionaries arrived in the late 19th century. But the hardships of Japanese occupation, the Korean War, dictatorial rule and contemporary anticommunist sentiments have caused most South Korea Christians to align not with peace and reconciliation but with nationalism, militarism and consumerism, united against the neighbor to the north.

The Pew Research Center found in 2010 that Christians make up South Korea’s second biggest religious group at 29%, behind only those with no religious affiliation. Six of the eight presidents South Korea has elected in the democratic era since 1987 have been Christians.

Christianity grew in the shadow of foreign rule by Japan, which lasted from 1910 until the end of World War II in 1945. A movement that started in 1919 in which 2 million activists called for independence was the world’s largest peaceful demonstration ever, and 15 of its 33 leaders were Christian. The events influenced nonviolent resistance in India and many other countries and are remembered with a national holiday on March 1.

“In Korea, Christianity was not the colonizer’s religion, so we didn’t think it was a bad Japanese thing,” said SeongHan Kim, Mennonite Central Committee’s Northeast Asia representative. “That’s one reason Christianity grew so rapidly. It was a way to overcome the Japanese occupation.”

Foreign rule was bitter colonialism, defined by Seodaemun Prison, an imposing brick facility and work camp for political prisoners. Many people died there from execution or torture, inspiring countless others to hold the Japanese empire — and its descendants — in contempt.

Now a museum comparable to German concentration camps, the prison is personal for Kim. His grandfather was tortured there as part of the armed resistance to Japanese rule.

“Growing up, that narrative was inscribed on my heart,” he said on May 31, just inside the prison’s main gate, as he reflected on his Christian upbringing and early 1990s mandatory military service. “But I’m also aware the ministry of reconciliation is not just ‘Kumbaya.’ . . . I believe for us as Christians, as Mennonite Central Committee, God has put us in this dark, very complex work. That’s the way we open our heart to the ministry of reconciliation.”

When the Japanese occupation of Korea ended in 1945, Koreans hoped to gain independence. Instead the United States and the Soviet Union split the peninsula hastily into two occupation zones, divided at the 38th parallel. The states of North and South Korea, clients of the superpowers, were established in 1948.

Christianity was not the only thing that grew in the shadow of imperialism. Socialism’s message of equality and sharing found converts among rural farmers and urban laborers weary of foreign rule and domestic collaborators. Christians had lived in large numbers in the north but fled the advancing communists, finding safety with the U.S. military to the south.

Tension mounted as clashes sprouted along an uneasy border, and rebellions grew among southern communists. Northern forces invaded the south on June 25, 1950, and nearly took the entire peninsula before a counteroffensive drove them back to the 38th parallel.

The southern half of the peninsula avoided the most severe fighting, leading to the imbalanced final body count. Up to 5 million people died related to Korean War violence, about 3 million in the north and 2 million in the south. The north, with a smaller population, lost a third of its people in three years. In the south, fewer than 1 in 10 died.

The nature of the fighting and Christianity’s role within it fit neatly into communist teaching. South Korean troops were issued crosses when they went into battle. U.S. troops carried Bibles. Indiscriminate U.S. aerial support killed civilian and soldier alike. The most common identifier to survivors sifting through invader corpses were the symbols of the church, reinforcing communist criticism.

When the war ended, the border between north and south was about the same as when it began. The U.S. kept about a quarter million troops there following the 1953 cease-fire, and about 28,000 remain, as of the last figures available in 2020.

Buoyed by American aid and U.S. military presence, South Korea’s economy boomed, but democracy lagged. The U.S. State Department’s handpicked rulers can be best described as dictators. Free and open elections did not come until 1987, the same year Seodaemun Prison closed.

As many South Korean Christians see it, prosperity has been proof of God’s blessing ever since, cementing a form of Christian nationalism unique to Asia.