I have often returned to a concept that has shaped Anglo-American strategic thinking since the nineteenth century: the rivalry between sea powers and land powers.
A sea power seeks what Alfred Thayer Mahan called command of the sea. With that command comes the ability to strike any country whose cities and industries lie near the coast, and to control the movement of goods across the world’s oceans. Even when it speaks of free trade, it is free trade under its own rules. The sea power ultimately decides who may ship what to whom.
Opposing it stands the land power—a state whose strength lies deep inland, beyond the easy reach of naval guns and carrier groups, or one capable of defending its coastline strongly enough to deny maritime domination.
In our own time, this strategic contrast is often described in terms of the rivalry between the United States—the world’s preeminent sea power—and the great land powers of Eurasia, above all Russia and China. By the traditional logic of sea power, the maritime side enjoys a structural advantage. The United States can intercept Russian shipping on the oceans; Russia could hardly respond in kind. At most it might inconvenience American freight moving along the Trans-Siberian Railway.
Could this balance change now that China has gained overwhelming industrial capacity and increasingly formidable technological capabilities? According to classical Mahanian logic, the answer would be straightforward: China should build a much larger fleet and challenge for command of the sea.
Yet everything we know about China suggests that it may not be eager to fight decisive naval battles for mastery of the oceans. Technological progress opens another possibility—one that Mahan himself could hardly have imagined: the control of space.
Whoever dominates activity in orbit may ultimately shape events both on the oceans and across the continents.
Perhaps this is only speculation. But the number of alternative paths is not very large.