Nation-states blend diplomacy with hard power to pursue their strategic interests abroad. One of the greatest military and diplomatic adversaries the U.S. deals with today is China. The United States and China clash in several areas, especially Taiwan and the South China Sea. China's "nine-dash line" envisions a sprawling maritime territory, and the nation is consistently engaged in activities to realize this vision. American foreign policy tools aimed at countering this desire include a partnership with Australia to supply mission-critical nuclear submarine technology to the ally (something that has angered another good friend in France). China and the U.S. are...