But great powers do not merely strive to be the strongest great power, although that is a welcome outcome. Their ultimate aim is to be the hegemon—which means being the only great power in the system.

What exactly does it mean to be a hegemon in the modern world? It is almost impossible for any state to achieve global hegemony, because it is too hard to sustain power around the globe and project it onto the territory of distant great powers. The best outcome a state can hope for is to be a regional hegemon, to dominate one’s own geographical area. The United States has been a regional hegemon in the Western Hemisphere since about 1900. Although the United States is clearly the most powerful state on the planet today, it is not a global hegemon.

States that gain regional hegemony have a further aim: they seek to prevent great powers in other regions from duplicating their feat. Regional hegemons, in other words, do not want peer competitors. Instead, they want to keep other regions divided among several great powers, so that those states will compete with each other and be unable to focus their attention and resources on them. In sum, the ideal situation for any great power is to be the only regional hegemon in the world. The United States enjoys that exalted position today.

What does this theory say about how China is likely to behave as it rises in the years ahead? Put simply, China will try to dominate Asia the way the United States dominates the Western Hemisphere. It will try to become a regional hegemon. In particular, China will seek to maximize the power gap between itself and its neighbors, especially India, Japan and Russia. China will want to make sure it is so powerful that no state in Asia has the wherewithal to threaten it.

It is unlikely that China will pursue military superiority so it can go on a rampage and conquer other Asian countries, although that is always possible. Instead, it is more likely that it will want to dictate the boundaries of acceptable behavior to neighboring countries, much the way the United States lets other states in the Americas know that it is the boss.

An increasingly powerful China is also likely to attempt to push the United States out of Asia, much the way the United States pushed the European great powers out of the Western Hemisphere in the nineteenth century. We should expect China to come up with its own version of the Monroe Doctrine, as Japan did in the 1930s.

These policy goals make good strategic sense for China. Beijing should want a militarily weak Japan and Russia as its neighbors, just as the United States prefers a militarily weak Canada and Mexico on its borders. What state in its right mind would want other powerful states located in its region? All Chinese surely remember what happened in the previous two centuries when Japan was powerful and China was weak.

Furthermore, why would a powerful China accept U.S. military forces operating in its backyard? American policy makers, after all, go ballistic when other great powers send military forces into the Western Hemisphere. Those foreign forces are invariably seen as a potential threat to American security. The same logic should apply to China. Why would China feel safe with U.S. forces deployed on its doorstep? Following the logic of the Monroe Doctrine, would China’s security not be better served by pushing the American military out of Asia?

Why should we expect China to act any differently than the United States did? Are Chinese leaders more principled than American leaders? More ethical? Are they less nationalistic? Less concerned about their survival? They are none of these things, of course, which is why China is likely to imitate the United States and try to become a regional hegemon.

WHAT ARE the implications of this security story for Taiwan? The answer is that there is a powerful strategic rationale for China—at the very least—to try to sever Taiwan’s close ties with the United States and neutralize Taiwan. However, the best possible outcome for China, which it will surely pursue with increasing vigor over time, would be to make Taiwan part of China.

Unification would work to China’s strategic advantage in two important ways. First, Beijing would absorb Taiwan’s economic and military resources, thus shifting the balance of power in Asia even further in China’s direction. Second, Taiwan is effectively a giant aircraft carrier sitting off China’s coast; acquiring that aircraft carrier would enhance China’s ability to project military power into the western Pacific Ocean.

In short, we see that nationalism as well as realist logic give China powerful incentives to put an end to Taiwan’s de facto independence and make it part of a unified China. This is clearly bad news for Taiwan, especially since the balance of power in Asia is shifting in China’s favor, and it will not be long before Taiwan cannot defend itself against China. Thus, the obvious question is whether the United States can provide security for Taiwan in the face of a rising China. In other words, can Taiwan depend on the United States for its security?

LET US now consider America’s goals in Asia and how they relate to Taiwan. Regional hegemons go to great lengths to stop other great powers from becoming hegemons in their region of the world. The best outcome for any great power is to be the sole regional hegemon in the system. It is apparent from the historical record that the United States operates according to this logic. It does not tolerate peer competitors.

During the twentieth century, there were four great powers that had the capability to make a run at regional hegemony: Imperial Germany from 1900 to 1918, Imperial Japan between 1931 and 1945, Nazi Germany from 1933 to 1945 and the Soviet Union during the Cold War. Not surprisingly, each tried to match what the United States had achieved in the Western Hemisphere.

How did the United States react? In each case, it played a key role in defeating and dismantling those aspiring hegemons.

The United States entered World War I in April 1917 when Imperial Germany looked like it might win the war and rule Europe. American troops played a critical role in tipping the balance against the Kaiserreich, which collapsed in November 1918. In the early 1940s, President Franklin Roosevelt went to great lengths to maneuver the United States into World War II to thwart Japan’s ambitions in Asia and Germany’s ambitions in Europe. The United States came into the war in December 1941, and helped destroy both Axis powers. Since 1945, American policy makers have gone to considerable lengths to put limits on German and Japanese military power. Finally, during the Cold War, the United States steadfastly worked to prevent the Soviet Union from dominating Eurasia and then helped relegate it to the scrap heap of history in the late 1980s and early 1990s.

Shortly after the Cold War ended, the George H. W. Bush administration’s controversial “Defense Planning Guidance” of 1992 was leaked to the press. It boldly stated that the United States was now the most powerful state in the world by far and it planned to remain in that exalted position. In other words, the United States would not tolerate a peer competitor.

That same message was repeated in the famous 2002 National Security Strategy issued by the George W. Bush administration. There was much criticism of that document, especially its claims about “preemptive” war. But hardly a word of protest was raised about the assertion that the United States should check rising powers and maintain its commanding position in the global balance of power.

The bottom line is that the United States—for sound strategic reasons—worked hard for more than a century to gain hegemony in the Western Hemisphere. Since achieving regional dominance, it has gone to great lengths to prevent other great powers from controlling either Asia or Europe.

Thus, there is little doubt as to how American policy makers will react if China attempts to dominate Asia. The United States can be expected to go to great lengths to contain China and ultimately weaken it to the point where it is no longer capable of ruling the roost in Asia. In essence, the United States is likely to behave toward China much the way it acted toward the Soviet Union during the Cold War.

China’s neighbors are certain to fear its rise as well, and they too will do whatever they can to prevent it from achieving regional hegemony. Indeed, there is already substantial evidence that countries like India, Japan and Russia as well as smaller powers like Singapore, South Korea and Vietnam are worried about China’s ascendancy and are looking for ways to contain it. In the end, they will join an American-led balancing coalition to check China’s rise, much the way Britain, France, Germany, Italy, Japan and even China joined forces with the United States to contain the Soviet Union during the Cold War.