Theoretically, America – whether led by Joe Biden, Kamala Harris or Donald Trump – should be trying to remain the world’s pre-eminent strategic power.
In international relations theory, the realist outlook maintains that the international system of states compels individual states to seek as much power over other states as possible. This is the only way to reliably make themselves more secure.
From here, there is a split between defensive and offensive realists.
Defensive realists believe that, as an individual state achieves relative strength over potential competitor states, it takes its foot off the accelerator and focuses more on maintaining the status quo than on building its lead.
Offensive realists believe a state can never have too much security, so states will never stop trying to gain additional relative power over other countries, all of which are potential adversaries. Any state that has the wherewithal will try to dominate its neighbors.
One of the most prominent American proponents of realism, University of Chicago professor John Mearsheimer, is in the offensive camp. His outlook predicts: “The United States is going to go to great lengths to make sure that China does not dominate Asia.”
Great lengths include going to war over Taiwan. Americans “would fight and die to defend Taiwan,” he believes.
He disregards questions about whether the US public would support such a war, saying the US government would “manipulate the discourse on what is going on in ways that present China as a mortal threat.”
Mearsheimer gives two reasons why Washington would try so hard to contain PRC expansionism.
First, the United States has global economic interests to protect. A potential adversary such as China gaining control over an important center of global markets, wealth and industrial capacity such as East Asia would threaten American prosperity. “It is clear from the historical record,” he writes, that “the US does not tolerate peer competitors.”
Second, Mearsheimer argues that a strong country that establishes domination over its region is “free to roam.” Not threatened by any of its own neighbors, it will make aggressive probes into some other major power’s neighborhood. So if the US wasn’t blocking Beijing’s control over areas of China’s near abroad such as Taiwan, the East China Sea and the South China Sea, China would be challenging US security in the Western Hemisphere.
Mearsheimer’s offensive realism, however, has a built-in flaw. Despite the logic that seemingly commits America to hanging onto strategic preeminence at all costs and making sure China does not attain hegemony over Asia, he acknowledges that governments, including that of the US, do not always act as his theory predicts.
For example, he says, it was “foolish” and a “strategic blunder” for the US to fuel China’s rapid economic growth and technological progress starting in the 1980s in the mistaken belief that this would preclude future security conflicts with China – an opinion that many other analysts now share.
In effect, Mearsheimer is saying his theory can reliably predict how major powers will behave given their external circumstances – but also that some countries, including the most consequential country on earth, refuse to behave according to his theory.
This would seem to allow for the possibility that, the pressures of the international system notwithstanding, a government might take power in the US that is no longer interested in preventing Chinese hegemony in East Asia.
This may in fact be happening.
Instead of an activist America that fosters liberal rules and institutions and seeks to shape regions throughout the globe to prevent the rise of strong adversaries, Trump’s vision seems to involve dividing the world into clearly-demarcated empires. His continuing talk about annexing Canada and Greenland seems like more than just a joke to discomfit his domestic political opponents.
There is some evidence Trump would also acquiesce to Russian and Chinese empires. His government has signaled acceptance of Russia keeping its recent territorial gains in Ukraine.
Recent statements by Trump’s controversial Defense Secretary Pete Hegseth and Vice President J.D. Vance have deepened European fears that Trump II intends to scuttle US security commitments to Western Europe.
Trump has frequently said the US alliances with Japan and South Korea are worthwhile only if America makes a profit from them. He has said little about the strategic importance of these alliances, which suggests he is not down with the cause of strategically containing China, even if some of his senior officials are.
Trump reportedly wants to withdraw US troops from South Korea. He has also said he has “no problem” with North Korea testing short-range missiles that cannot reach the US, even though such missiles threaten South Korea. It appears Trump would be amenable to terminating US responsibility for South Korea’s defense if this would also take America off Pyongyang’s target list.
As for the possibility of US intervention in a Taiwan Strait war, Trump has said Taiwan is indefensible and is unimportant compared with China – and that he resents Taiwan for allegedly “stealing” the semiconductor manufacturing business from the US.
If Trump sees China as a threat, it is as an economic threat, and one that he would address primarily through economic policy rather than military strategy.
Tariffs have been his preferred tool. Trump believes tariffs can balance the US trade deficit and incentivize manufacturing to move to the US. In late 2024 Trump said in an interview with the Wall Street Journal that he would respond to a PRC attack on Taiwan by imposing high tariffs on China, not by sending US forces to help.
Contrary to Mearsheimer’s expectation, Trump seems not to fear that a Chinese hegemony over Asia would seriously jeopardize US prosperity.
Despite China’s impressive economic development, accumulation of wealth and military buildup, America is still the world’s leading economic, military and innovation power. Washington also has a network of strong allies, unlike China.
It has not become unfeasible for the US to continue to promote global arrangements based on liberal principles that serve US interests, or to resist Chinese expansionism in East Asia. Rather, the Trump II administration may be choosing to let Pax Americana die in a case of domestic politics triumphing over international imperatives that are clearly not irresistible.
Denny Roy is a senior fellow at the East-West Center, Honolulu.
