Following weeks of heightened rhetoric, Secretary of Defense Chuck Hagel's recent statement, and the news that new North Korean missile testing could take place any day now, tensions on the Korean Peninsula remain at a historic high. If a war were to take place, what could it look like? This is a question that is difficult to answer because of the uncertainty surrounding the insular North Korean regime.
Most analysts agree that North Korea is not ready to deliver a nuclear payload yet, however when it comes to conventional forces North Korea is well-equipped. It features a standing army of 1.1 million and may be able to fire as many as 500,000 rounds of artillery into Seoul in just the first hour of a conventional conflict. In fact, according to a simulation conducted in 2005, a conventional conflict could easily yield up to 100,000 causalities in South Korea alone within the first few days.
An older estimate of a "conventional war" would not take into account the cyber arena. North Korea certainly has offensive cyber capabilities and has probably already used them against the South. The U.S is assumed to have the greatest offensive cyber capabilities in the world, but defining the types of damage that it would be capable of doing is impossible except in theory. In the cyber world however, North Korea's archaic weaponry and limited network connectivity would be an advantage.
Could the regime even survive during a conflict? A former officer who fled North Korea described a much less cohesive picture in the country, including apparent dissension in the military ranks during Kim Jong-un’s rise to power. The nation still has memories of U.S. bombers flattening North Korea 60 years ago (a fear not lost on the U.S. when it did a large-scale fly-by this week) and hundreds of thousands may flee to the Chinese border at the first hint of large scale bombing. China's role cannot be underestimated and they are reportedly not entirely sold on Kim Jong-un in the first place. Entangling the United States in a messy conflict and supporting a long time ally would not be worth the refugee crisis or a new, potentially unified, and Western-aligned Korea on its borders. Chinese support would be essential to the regime, but it seems like their powerful ally would be anything but enthusiastic.
The most likely scenario would be continued probing of the international system and its limits by the North Korean government. This has happened as recently as 2010 with the sinking of the South Korean ship ROKS Cheonan by a North Korean submarine. Even a ballistic missile launch against Southern targets by the North Koreans would not immediately trigger a full-scale conventional war, assuming it does not have a chemical warhead. Shots could be fired, and low-intensity conflict could ensue with small-scale artillery and missile exchanges before the most powerful actors, U.S. and China, are able to reel both sides back in.
Although it's hard to imagine a large-scale conventional war in the current international system, North Korea is an anomaly in the modern world: an isolated, personalistic regime with one of the largest conventional militaries on Earth. This, combined with Kim Jong-un's young age and inexperience, makes a full-scale conflict not completely out of the realm of possibility.