The United States and South Korea ended 2018 without coming to an agreement on a cost-sharing agreement for the next five-year period of allied operations. This meant that the previous agreement—the Special Measures Agreement (SMA), as it’s known—expired on December 31.

The inability of the two sides to conclude an SMA represents a significant challenge to the future of their alliance—a challenge that is amplified by the upcoming prospect of a summit meeting between U.S. President Donald Trump and North Korean Kim Jong Un towards the end of February 2019.

The conclusion of