The U.S. and South Korea have spent almost seven decades honing their preparedness for war. Now fears are growing among the alliance's proponents that extended peace talks are eroding that advantage.

Defense chiefs from the two nations will gather for an annual meeting in Washington on Wednesday facing a radically changed landscape after President Donald Trump's decision to restart nuclear negotiations with North Korean leader Kim Jong Un. While those discussions put off the prospect of a conflict, Trump has also canceled major military exercises to facilitate the detente.

Secretary of Defense Jim Mattis and his South Korean counterpart, Jeong Kyeong-doo, must now find a way to maintain a robust defense without providing regular, real-world simulations for troops that tend to rotate through every couple of years. Trump's statements calling the exercises "war games" and echoing Kim by calling them "provocative" makes them harder to restart as long as nuclear talks drag on.