Because it’s all about deterrence.
The Kim dynasty in North Korea has given its military a formidable task—maintaining a threat posture towards it dramatically wealthier neighbor to the south, which also happens to be allied to the greatest military power on the planet. It’s estimated that North Korea spends only between six and ten billion dollars annually on a defense. That amount is over two orders of magnitude less than the United States does. But that spending amounts to roughly twenty five percent of North Korea’s GDP, compared to between 3.5 percent for the United States
Given these stark disparities, the Korean People’s Army’s (KPA) leaders have arguably ceased planning to win a war versus the South, instead aiming to endure one. For example, the KPA has selectively invested in tactics and technology that would make such a conflict as painful as possible for South Korea, Japan and the United States.
A Million Man Army
Though North Korea only has a population of twenty-five million, the Korean People’s Army is amongst the largest in the world, counting around a million personnel. All adult males are mandatorily conscripted for three years of military service, and tens of thousands of women also volunteer to serve in ground, aviation and intelligence units, though conditions are reportedly brutal. There are additionally three to five million reservists in the Worker-Peasant Red Guard militia.