In the Korean peninsula, a costly game of one-upmanship

North Korean leader Kim Jong Un is going as far as possible without going to war. He is showing what he might do if sufficiently threatened by his enemies, the South Koreans under the conservative President Yoon Suk-yeol buttressed by their American ally. And he's got his armed forces promising "sustained, resolute and overwhelming practical military measures," unspecified but intended to be taken seriously. Similarly, the U.S. and South Korea have put on a show of their own defensive/aggressive capabilities. Like the North Koreans, they stopped short of attacking North Korean facilities while demonstrating their tremendous fire power and prowess…