Alliance is not charity. It's strategy

Chun In-bum

For many Americans, especially in the Trump era, alliances are increasingly judged by one question: What does America get out of them?

That is a fair question. The answer is that the alliances with South Korea and Japan are not acts of generosity. They are among the most cost-effective strategic investments the United States has anywhere in the world.

The old language of “shared values” and “historic friendship” still matters, but it is no longer enough. If Seoul and Tokyo want to remain central to Washington’s strategy, they must frame the alliance not as something America should preserve for moral reasons, but as something that directly serves American interests.

South Korea and Japan are not simply beneficiaries of American protection. They are forward operating platforms for American power in the Indo-Pacific.

Without Japan, the United States would struggle to sustain naval and air operations across the Western Pacific. American bases in Japan allow rapid access to the East China Sea, the Taiwan Strait and the Korean Peninsula. Without South Korea, the United States would face far greater difficulty deterring North Korea, monitoring Chinese activity and maintaining a credible military presence near the Asian mainland.

The blunt reality is this: If the United States withdraws from Korea and Japan, China would gain strategic space almost immediately.

That is why even an “America First” administration cannot simply walk away from Asia. The Trump administration’s National Defense Strategy makes clear that the central challenge for the United States is China, particularly around Taiwan and the First Island Chain. Washington may expect allies to carry more of the burden, but that is not the same as abandoning them.

In fact, the alliance argument becomes stronger under an “America First” framework.

Washington is no longer interested in alliances where America pays, America fights, and allies simply watch. It wants allies that spend more, build more, produce more and contribute more. Japan has already moved in that direction with higher defense budgets, counterstrike capabilities and stronger defense industrial cooperation. South Korea has become one of the world’s major arms exporters and has developed major strengths in shipbuilding, missile defense, semiconductors and munitions production.

Japan and South Korea help America in areas where the United States itself is struggling. America has a shrinking defense industrial base, shortages in shipbuilding capacity and increasing concerns about semiconductor supply chains. South Korea and Japan can help solve those problems.

South Korea’s shipyards can build naval vessels faster and more cheaply than most American yards, while Japan remains one of the world’s most advanced producers of industrial technology and maritime capability. Together, they provide industrial depth that America would struggle to recreate on its own.

This matters because a conflict with China would not only be fought through warships and fighter aircraft. It would also be fought through logistics, semiconductors, ship repair, fuel supplies, cyber resilience and industrial endurance.

There is another uncomfortable truth that many in Japan increasingly understand, even if they do not always say it publicly: South Korea is central to Japanese security.

Historically, Japanese strategists have long viewed the Korean Peninsula as either a defensive shield or a dangerous vulnerability. If a hostile power dominates Korea, Japan becomes far more exposed. Chinese or North Korean military control, influence or coercion over the peninsula would place direct pressure on Japan’s sea lanes, western coastline and approaches to the Sea of Japan and East China Sea.

A weakened or unstable South Korea would force Japan to divert more resources to its own defense, expand maritime patrols, strengthen missile defenses and prepare for greater threats around Kyushu and the Tsushima Strait. It would also make it easier for China and North Korea to coordinate pressure on Japan from multiple directions.

In simple terms, if South Korea falls into chaos, strategic paralysis or Chinese domination, Japan would be next in line for greater coercion. Japan’s security begins well before an adversary reaches Japanese territory. It begins on the Korean Peninsula.

That is one reason Japan has become more supportive of trilateral cooperation with the United States and South Korea. Tokyo understands that the defense of Korea is not simply about helping an ally. It is also about protecting Japan itself.

North Korea remains dangerous, but it is no longer the only reason the alliance exists. The broader issue is preventing China from dominating Asia. If China controlled the Taiwan Strait, intimidated Japan, weakened South Korea and pushed the United States out of the region, the economic and strategic consequences for America would be enormous.

Roughly one-third of global trade passes through the South China Sea. Much of the world’s advanced semiconductor production sits in Taiwan, South Korea and Japan. If China dominated that geography, the United States would face higher costs, weaker supply chains, less freedom of maneuver and a more dangerous military balance.

In other words, the United States needs Korea and Japan not because it loves alliances, but because it cannot effectively compete with China without them.

There is also an uncomfortable truth that many in Seoul and Tokyo do not want to hear: If South Korea and Japan cannot work together, their value to the United States declines.

Washington does not want to spend endless time mediating historical disputes, trade fights or intelligence-sharing breakdowns between two of its closest allies. The United States wants an integrated regional framework where Japan, South Korea, Australia, the Philippines and others cooperate in practical ways.

For South Korea, the lesson is clear. If Seoul wants to keep strong support in Washington, it must stop presenting the alliance primarily as a favor to Korea. It must present itself as an indispensable partner in helping America deter China, strengthen supply chains, expand shipbuilding, produce weapons and maintain the regional balance of power.

That is the language Washington increasingly understands.

Alliance is not charity. It is not sentiment. It is not nostalgia.

It is leverage, geography, industry, deterrence and power.

And for the United States, Japan and South Korea remain two of the most valuable strategic assets it has. Still, a word of warning to both progressives and nationalists in Korea: Do not assume that the United States will tolerate endless anti-Americanism while continuing to provide security guarantees, as the Philippines learned in the early 1990s.

Retired Lt. Gen. Chun In-bum is the former commander of the Republic of Korea Army Special Warfare Command.