They can also be built through tariffs, economic sanctions, and technological restrictions.” The New Walls of PowerThroughout much of the twentieth century, international trade was presented as one of the principal engines of cooperation among nations. Trade as a Geopolitical WeaponThroughout much of the twentieth century, international trade was understood as a mechanism for increasing shared prosperity. Twenty-first-century geopolitics combines military power, economic strength, technological innovation, and industrial capacity in a single equation. Economic power has become one of the principal tools of contemporary geopolitics.