Many people see America as a new Roman Empire but few, if any, believe it can rule the world as Solo Superpower and through globalization. Moreover, not far into this decade, it will become evident that four other empires have been arising to challenge America. Three criteria for empire in this new century are large landmass, an educated elite and a nuclear weapons delivery capability. Russia has met all three since the late 1950s, China since the late 1970s, India in the late 90's. Iran, while it lacks landmass, could fulfill the other two criteria in this decade.
Historians know that a country which has been an empire finds that difficult to forget.
India was an empire from 264 BCE till 1857, then part of the British Empire till 1947. China was an empire from 221 BCE to 1911, Russia from 1472 till 1917. During the Cold War, from 1947 to 1991, American strategic planners focused on the Soviet threat. But now Pentagon planners see imperial threats coming from Asia. A Joint Chiefs of Staff report says the Asian continent and its oceans are the most likely sites of conflict for the next two decades.