(1) Historical factors have combined to produce a fiercely nationalistic population on both sides of the DMZ.
Multiple kingdoms existed on the Korean Peninsula from the first century. (So one might say Korea is five times as old as the United States.) From 936 to 1910, Korea constituted a single state, embracing the whole peninsula, populated by a relatively homogeneous people. The division of the last 82 years is anomalous. Koreans feel a deep sense of national historical victimization—especially by Japan and the U.S.—but have suffered many invasions in their long past. The Jurchens (from 10th century), Mongols (1231), Japanese (1592-98), Manchus (1627), and Japanese again in the twentieth century, and then the Americans. Most Koreans of my acquaintance express themselves passionately about this legacy of abuse, and commitment to eventual reunification following the 1945 division they properly blame mostly on the U.S. You don’t want to provoke Koreans with schoolyard bully talk.
(2) Korean culture has derived much from Chinese culture for 2000 years, and China has influence. But China doesn’t control Korea.
While Korean culture is unique, it has (like Japanese and Vietnamese cultures) been deeply influenced by China and Confucianism in particular. For a thousand years, Korea was one of China’s tributaries, enjoying the right to trade in China in return for its kings’ formal acceptance of vassal status. Koreans have traditionally viewed China as a friend and protector. But not always. There have been periods of high tension, as during the Cultural Revolution when the Red Guards condemned Kim Il-song. China is unable to control North Korea or events on the whole peninsula.
(3) The relationship between Japan and Korea has been mostly bad for 800 years, and bad relations prevail now between Japan and both Koreas.
Relations between Korea and neighboring Japan have often been tense or hostile. From the 13th to 16th centuries, Japanese pirates raided the Korean coasts. An invasion of Korea by Japan between 1592 and 1598 killed around 200,000 and resulted in the enslavement of thousands. After the Russo-Japanese War, Japan colonized Korea, imposing an oppressive and humiliating regime that at one point obliged Koreans to adopt Japanese names. There have been times of mutual respect: during the Edo period (1603-1868) the only states with which Japan maintained diplomatic relations were Korea and the Ryukyu Kingdom (annexed by Japan in 1879). Korean envoys regularly visited Japan during a time of “national seclusion.” But much anti-Japanese sentiment lingers in Korea, on both sides of the DMZ, understandably.
(4) The partition of Korea into north and south is a product of the Cold War and U.S. policy.
In the final weeks of World War II, the U.S. and its wartime ally, the USSR, simultaneously occupied the Korean peninsula and accepted the Japanese surrender. The Russians arrived first, through Manchuria, advancing as far as the 38th parallel where they stopped by agreement with the U.S. U.S. forces arrived soon thereafter and occupied the south. The division was meant to be temporary; Stalin wanted immediate independence for Korea. But the U.S., which initially ordered Japanese administrators to remain at their posts, and viewed Korea as occupied enemy territory, did not want to risk the prospect of a Korea united under communist rule. There was much leftist opposition to the occupation of the south; the U.S. suppressed the “People’s Republic of Korea” that had been pronounced in Seoul in the last days of the war and the popular committees wherever they had been established. In 1948 the U.S. unilaterally proclaimed the formation of the Republic of Korea, sealing the division of the peninsula; the DPRK was proclaimed in the north only afterwards. Soviet troops withdrew; U.S. troops stayed.
(5) The war caused by the partition and the expression of Korean anti-imperialist nationalism was horrible.
In 1950 the North invaded the South to achieve reunification under the North’s terms. It almost succeeded. There was widespread support for the northern troops; southern resistance quickly buckled and held out only around Pusan in the southeast. The U.S. organized a counterattack, using the Soviet ambassador’s absence from the UN Security Council (to protest the failure of the Council to confer China’s seat on the newly-established People’s Republic of China and leave it with the Republic of China on Taiwan) to push through a resolution authorizing war to repulse the invasion. The U.S. war objective was to reunify the country under U.S. hegemony; Gen. Douglas MacArthur was eager to use nuclear weapons to do this, although he was prevented from doing so by President Truman. China naturally aided its ally in Pyongyang, repulsing the U.S.-led forces’ advance and driving them down to the 38th parallel. The war that killed three million (and perhaps 30% of the northern population) ended in an armistice that has held since 1953. (Japan, Korea’s old foe, profited mightily from the war; indeed its economy returned to its 1938 level by 1953 due to U.S. “special procurements” in connection to the war.)
(6) The U.S. has abetted oppression in South Korea ever since.
After the war, the U.S. maintained, as it continues to maintain, military bases supporting tens of thousands of troops. It has deployed tactical military weapons on the peninsula. It supported a succession of dictators in Seoul to 1988. These included the notorious Park Chung-hee, father of the recently ousted president, assassinated by his intelligence chief. Park had a political opponent kidnapped from a Tokyo hotel and planned to execute him before the U.S. intervened. The stagnant economy grew under his rule, but so did dissent and oppression. The Gwangju Uprising of 1980, when Park’s successor Chun Doo-hwan was in power, over 600 students were killed by government forces, including military troops redeployed with U.S. concurrence. The NBC coverage of the 1988 Seoul Olympics showed Koreans booing the American athletes at the opening ceremony. One should not suppose that in the event of a U.S. attack on the north they would favor the U.S. over their compatriots.
(7) North Korea has been able to endure great hardship and rebound. It has been growing in recent years.
The North Korean economy quickly rebounded after the war, and its GDP kept pace with that of the South to the 1980s, when stagnation followed by steep decline set in. But in the eighties, per capita energy consumption in the North exceeded that of the South. (Think of that when you see those satellite images of a south illuminated at night while the shape of North Korea appears a black hole.) The collapse of the Soviet Union in 1991 and the flooding and famines from 1994 to 1998 produced calamitous decline, and caused the DPRK to lag further and further behind the south. But there has been steady recent growth; 70% of Pyongyang’s residents have cell phones and there is a building boom. One should not assume that more sanctions will close the country down or stymie whatever nuclear plan is in place.
(8) South Korea as well as North Korea has sought nuclear weapons.
Park Chung-hee openly announced South Korea’s interest in nuclear weapons in 1975. In 2004 Seoul admitted to the IAEA details of a secret nuclear program. Its scientists had enriched uranium to near-weapons grade using laser enrichment and conducted an experiment extracting plutonium in the 1980s and continued doing so until at least 2004. One should not forget that many countries have had secret nuclear weapons programs, including many U.S. allies such as Brazil and the Shah’s Iran, and that their development, however terrible, is not necessarily a specific threat to the U.S.
(9) The North Korean nuclear weapons program could have been suspended from 1989 through a U.S.-DPRK agreement.
The North’s nuclear program dates back to the 1950s but Pyongyang signed the Non-Proliferation Treaty in 1985. U.S. intelligence by 1989 concluded that the DPRK was in the early stages of building a nuclear bomb. But following protracted negotiations the U.S. and DPRK signed the “Agreed Framework” in which North Korea agreed to freeze its plutonium production program in exchange for fuel oil, economic cooperation, and the construction of two modern light-water nuclear power plants. According to the pact, the existing nuclear facilities were to be dismantled, and spent reactor fuel taken out of the country. But this agreement was virtually sabotaged by Congress and the Bush/Cheney administration, causing Pyongyang to withdraw from the NPT in 2003 and resume work for purposes of self-defense.
(10) If you make war on Korea, you make war on China.
Chinese forces drove the Japanese invaders from Korea in the 1590s, and the Americans from the DPRK in the Korean War. A 1961 treaty between China and North Korea requires both sides to take all necessary actions to oppose any attack by a third party or coalition. It has been renewed to 2021. But CNN, MSNBC and Fox have already told you that.