Image provided by Thomas Classen, Flickr.com.
Every American who has binge-watched a K-drama or waited in line for Japanese food has cast a quiet vote in one of the most consequential alliance debates in Asia.
When South Korea finalized its trade deal with the United States in 2025, the price of avoiding steeper tariffs was a $350 billion investment pledge, $150 billion of which was earmarked for a shipbuilding initiative named “Make American Shipbuilding Great Again.” Japan paid even more at $550 billion. In the United States’ current foreign policy, even its closest allies must pay to keep their place.
This poses a hard question for Tokyo and Seoul, neither of which can match China’s military power or economic reach and neither of which can count on an American president who treats alliances as contracts. Yet both hold an asset that Beijing has not managed to build: Americans genuinely like them. In an age of transactional diplomacy, that goodwill is not just a luxury, it is an insurance policy.
In a March 2026 Gallup survey, 85% of Americans viewed Japan favorably, one of the highest ratings Gallup has recorded since it began tracking Japan in 1989. In 2002, Americans viewed South Korea by a modest margin of 54% to 33%, and by 2025 62% held a favorable view.
That shift was not accidental. Over two decades, Seoul invested heavily in exporting its films, dramas, music, and cuisine, while Japan's anime, food, and travel industries reached billions. Tourism followed, with Japan welcoming a record 42.7 million foreign visitors in 2025. Every trip, meal, and show builds familiarity that holds political weight.
China’s approach offers a contrast. In November 2025, Prime Minister Sanae Takaichi told Japan’s parliament that a Chinese attack on Taiwan could justify a Japanese military response. Beijing retaliated by urging its citizens to stop traveling to Japan, and the number of Chinese tourists visiting Japan fell 45% in December 2025. Even so, Japan’s total number of foreign visitors from all countries reached a record high for the year, buoyed by rising arrivals from Australia, Europe, and the United States.
Still, soft power has real limits. South Korea’s admired culture did not win the 2030 World Expo, and goodwill did not spare either country from tariff pressure. The clearest warning came on September 4, 2025, when federal agents raided a Hyundai-LG battery plant under construction in Georgia and detained 475 workers, most of them South Korean nationals. Images of workers in shackles shocked South Koreans, while President Donald Trump said ICE was simply doing its job. American affection for K-dramas and K-pop did nothing to shape that decision. Public support defending South Korea also eroded, with the share of Americans willing to send troops if North Korea invaded South Korea fell from 62% in 2017 to 50% in 2023.
However, these limits clarify the argument rather than dismantle it. Soft power does not deter North Korean missiles or Chinese coast guard ships, which is why Japan is expanding its defense capabilities and South Korea maintains one of Asia’ strongest militaries. Culture works on a different target: the American voter. It raises the domestic cost of abandonment and keeps an ally’s case alive in Congress and in the public opinion when negotiations turn sour.
Tokyo and Seoul should treat cultural diplomacy as alliance strategy, not as a branding exercise. That means investing in student and professional exchanges and building ties with the states that host their factories and the members of Congress who represent them. The recent visits between Prime Minister Takaichi and President Lee Jae-myung show how personal diplomacy can strengthen ties that once seemed fragile.
While China might have the larger navy and deeper pockets, Japan and Korea have something harder to build: an American public that sees them as friends. In a transactional age, that may be the most valuable term in the contract.