Physically, THAAD serves as an Iron Curtain to intercept incoming missiles from North Korea. Separate national security interests have supplanted Cold War ideology, but THAAD could influence competing alliances and block cooperation among the countries involved in the “Six Party Talks.”

The Trump administration has been surprisingly brusque with demands that NATO allies meet their financial defense targets quickly. However, the US push for more military spending by European allies is less about European security than about freeing up more of Washington’s own resources to deal with issues in Asia.