When Allies Ask You to Take the Lead: Korea's New Defense Role

When Elbridge Colby, the US Under Secretary of Defense for Policy, called his recent Seoul meetings "excellent," he wasn't just being diplomatic. He was celebrating a fundamental shift in one of America's oldest alliances—one that places South Korea in the driver's seat for its own defense against North Korea.

The 70-Year Alliance Gets a Makeover

During his January 25-27 visit to Seoul, Colby met with top Korean officials including National Security Adviser Wi Sung-lac, Defense Minister Ahn Gyu-back, and Foreign Minister Cho Hyun. The discussions centered on "modernizing" the bilateral alliance, but the subtext was clear: America wants Korea to take "primary" responsibility for conventional defense against North Korea.

This represents a seismic shift from the traditional model where the US provided the security umbrella while Korea played a supporting role. Now, as outlined in the Pentagon's new National Defense Strategy, America will offer "critical, but more limited" support while Korea leads the charge.

The timing isn't coincidental. With China's rise forcing Washington to focus on homeland defense and broader Indo-Pacific competition, the US can no longer afford to concentrate resources solely on the Korean Peninsula. Korea's commitment to boost defense spending to 3.5% of GDP—up from the current 2.8%—signals Seoul's readiness to shoulder this burden.

The Logic Behind the Shift

From Washington's perspective, this transition makes strategic sense. South Korea has evolved from a war-torn nation requiring protection into an economic powerhouse with advanced military capabilities. Korean companies like Samsung and LG produce cutting-edge defense technologies, while the country's shipbuilding prowess contributes to naval strength.

Moreover, Korea understands the North Korean threat better than anyone. Seoul has lived with this challenge for decades and has developed sophisticated intelligence and defense systems specifically tailored to counter Pyongyang's tactics.

For Korea, assuming primary responsibility could mean greater autonomy in handling North Korean provocations and more influence over US policy decisions affecting the peninsula. No longer would Seoul have to wait for Washington's lead on every major move.

The Skeptical View

But critics question whether Korea can truly handle North Korea's nuclear and missile threats independently. Despite its economic success, South Korea still relies heavily on US extended deterrence—particularly the nuclear umbrella—to counter Pyongyang's weapons of mass destruction.

There's also the broader regional context to consider. With China and Russia increasingly supporting North Korea, can Seoul effectively manage this challenge alone? The recent strengthening of the Moscow-Pyongyang partnership, including potential military cooperation, adds complexity that extends beyond the bilateral Korea-North Korea dynamic.

Domestically, Korean taxpayers might question whether the massive defense spending increase—potentially exceeding $150 billion annually—is worth the added responsibility, especially if US support becomes "more limited."

Alliance Evolution in Real Time

What we're witnessing isn't just a policy adjustment—it's the evolution of how modern alliances function in a multipolar world. The traditional patron-client relationship is giving way to a more equal partnership where both sides contribute according to their strengths and interests.

This model could serve as a template for other US alliances facing similar pressures. Japan, Australia, and European NATO members are all grappling with demands to increase defense spending and take greater security responsibilities.

Yet the success of this transition depends on maintaining trust and coordination. If Korea feels abandoned or the US becomes too detached, the alliance could weaken precisely when regional tensions are rising.