When people talk about hegemony today, they are usually referring to the United States, which is often described as a global hegemon. However, I do not believe it is possible for any country—including the United States—to achieve global hegemony. One obstacle to world domination is that it is very difficult to conquer and subdue distant great powers, because of the problems associated with projecting and sustaining power over huge distances, especially across enormous bodies of water like the Atlantic and Pacific Oceans. This problem is less acute when dealing with minor powers, but even so, the power of nationalism makes it extremely difficult to occupy and rule a hostile country. The paramount goal a great power can attain is regional hegemony, which means dominating one’s surrounding neighborhood. The United States, for example, is a regional hegemon in the Western Hemisphere. Although it is plainly the most powerful state on the planet by far, it is not a global hegemon.