By Mehmer Enes Beşer
The U.S.–Japan relationship has been framed for decades as the keystone of stability in East Asia, a union of American military clout and Japanese economic clout. For years, this two-nation coalition has operated on an unofficial arrangement: Japan would allow American bases on its territory and have its foreign policy harmonized with Washington, and the U.S. would provide a stable security canopy and reap robust economic ties. But with Donald Trump’s return to the White House and fresh threats of across-the-board tariffs on imports from Japan, that equilibrium hangs in the balance. The alliance will continue to exist in theory—but the breakdown of trust among one another in the shadows is something that makes it questionable for how long that will be able to continue.
Trump’s first term left a legacy of bruised allies and rattled institutions, and Japan wasn’t immune. His claim that Japan “takes advantage” of the U.S., his repeated demands for higher host-nation support payments from American soldiers, and his decision to pull out of the Trans-Pacific Partnership (TPP)—something Tokyo had urged him strongly not to do—urged Japanese leaders to a position of guarded optimism and guarded diplomacy. Prime Minister Shinzo Abe notoriously bet big on Trump personal chemistry, even presenting him with a gold golf club, in an effort to shield the alliance from the tempest. While this charm offensive may have sustained strategic alignment in the short run, it also demonstrated a deeper vulnerability: the relationship was becoming more performative than principled.
Today, in Trump’s potential second term, that vulnerability could become structural. His proposed 10% across-the-board tariff on imports—and tougher tariffs aimed at those countries with trade surpluses with America—most directly threatens Japan’s export-based economy. These sensitive sectors such as autos, electronics, and precision machinery, already highly dependent on access to the U.S. market, already are gearing up for another episode of uncertainty. But beneath the economic impact of tariffs is an even more corrosive danger: that America’s defense alliances no longer are separated from its economic grievances.
This is a profound departure from traditional American policy. Washington once did consider its alliances to be strategic public goods—mutually beneficial arrangements that served to maintain regional stability. Economic disagreements, though frequent, were administered through institutionalized channels and unbundled from defense ties. Trump’s policy blurs that distinction. To Trump, alliances are business deals, and strategic loyalty is an item to be bargained. On such a deal, Japan’s decades of loyalty to the alliance—its pacifist constitution, its stable diplomacy, its host-nation support—is all useless if the trade balance is perceived to be against it.
Tokyo’s interests are at stake. Japan is confronted today with a complicated security situation of expansionist China, nuclear-armed North Korea, and the unpredictability of Taiwan. All of this is not merely essential for the relationship with the United States—it is life and death. But if economic uncertainties lead Japan to believe it cannot rely upon America, and that US credibility is in doubt, it can begin to look for alternative options in steps: increased defense collaboration with Britain, Australia, or France; accelerated indigenous weaponry technologies; and even incrementally moving into a posture of strategic independence.
Indeed, Japan has already begun to do just that. Japan’s 2022 National Security Strategy was a historic step, vowing to double defense spending and develop counterstrike capacity—steps unthinkable a decade ago. Partly inspired by outside pressure, they are also signs growing in Tokyo of awareness that it can no longer rely on a politically volatile teeter of an ally to take care of its defense. Trump’s economic nationalism only accelerates that awareness.
Also, the larger regional interests have to be considered. If Japan loses faith in American reliability, other American friends and allies, particularly those in Southeast Asia and the Pacific, will not sit idly by. The impressions that Washington’s commitments are premised on trade advantage or political alignment undermine the credibility of so-called “free and open Indo-Pacific” strategy. China, ever attuned to shifts in alliance psychology, will seize the first chance to portray itself as the less volatile, if not more bountiful, partner.
Ironically, Trump’s personal routines will nullify the strategic competition with China he claims to want. Vanquishing faith in allies like Japan does not enfeeble China, it fortifies it. In an age where security and economic realms are increasingly blurring, credibility must be constructed. Betray Tokyo financially, and it will struggle to emotionally or strategically commit to the partnership.
Conclusion
The U.S.–Japan relationship has weathered many a storm, but Trump’s second-term economic nationalism can create a more profound break—one not rooted in policy disagreement, but loss of confidence. Tariffs, which were once seen as economic tools, now are symptomatic of strategic doubt. Japan can still smile and shake hands, but its strategic minds must be working up contingencies in private.
The coming years will tell whether the partnership will be one of equality of equals, or whether it will sink into a bog of transactionalism and suspicion. To America, holding on to its leverage in East Asia requires more than brutes—it requires being firm, being respectful, and that grand-power politics begins with loyal friendship. To Japan, it is as nuanced a test: weathering the storm without losing its anchor.
Trump’s economic wave won’t take down the U.S.–Japan alliance overnight. But it’s already causing waves.