As America's top diplomat, Secretary of State Mike Pompeo must pursue good relations with foreign powers and also speak up for American interests.

For that reason, Pompeo deserves credit for challenging the South Korean government's recent deal to suspend military drills along the Korean Demilitarized Zone. South Korea made clear on Wednesday that Pompeo had expressed his strong displeasure over that deal. The South Koreans say that these suspended drills reduce the risk of an inadvertent military exchange and ameliorate broader tensions. But they're wrong, because the South Korean approach here actually fosters two negative outcomes: It endangers U.S. military forces and it emboldens hardliner elements in the North Korean regime.

On the first point, the reduction of military operations along the Demilitarized Zone, the challenge is diminished military readiness. Removing land mines that would obstruct North Korean incursions and canceling operations alongside the U.S. military, the South Korean armed forces are losing their competency and readiness. Remember, training is the critical ingredient of military capability. But with tens of thousands of U.S. military personnel stationed in South Korea, the decline in that nation's military readiness means that U.S. forces now face more risks. That is rightly unacceptable to the Trump administration.

The second factor of concern is how this South Korean appeasement will encourage the North Koreans to take a harder negotiating line towards the U.S. With Kim Jong Un yet to decide whether to embrace the U.S. offer of rapprochement in return for nuclear disarmament, any easy submission by Seoul empowers those around the North Korean leader who prefer the old Pyongyang game of foreign policy. Their number, among them Kim Yong Chol, believe North Korea should play for time and concessions from the U.S. while also dangling the possibility of a military attack on South Korea. This, they believe, is the surest path to extract economic concessions.

Ultimately, however, Pompeo's anger is necessary for a far simpler and more alarming reason. Because South Korea's decisions here only reflect its broader appeasement strategy. President Moon Jae-in's administration has decided that it is best to give North Korea just about whatever it wants. And while that strategy is ultimately likely to backfire on Seoul, as it always has before, America's harder-edged negotiating strategy now lacks a South Korean partner.