South Korea Wants Primary Defense Role as Trump Reshapes Alliance

When your defense budget is 1.4 times larger than your adversary's entire economy, shouldn't you be able to defend yourself?

That's the pointed question South Korean President Lee Jae-myung posed Saturday as he welcomed the Pentagon's new National Defense Strategy, which calls for Seoul to take "primary" responsibility for deterring North Korea while receiving "critical, but more limited" U.S. support.

"In the midst of an unstable international security situation, achieving self-reliant defense is the most basic of basics," Lee wrote on X, embracing what many allies might view as an American retreat. His response signals a remarkable shift in how South Korea views its role in the decades-old U.S.-ROK alliance.

The Numbers Behind Seoul's Confidence

Lee's confidence isn't unfounded. South Korea commands the world's fifth-largest military and maintains defense spending that dwarfs North Korea's entire GDP. The country plans to boost military expenditure to 3.5 percent of GDP "as soon as possible" – a figure that would rival Israel's defense commitment and far exceed NATO's 2 percent target.

The timing aligns perfectly with Seoul's long-standing goal to reclaim wartime operational control (OPCON) from Washington by 2030, the end of Lee's presidential term. For decades, U.S. commanders would lead combined forces in any Korean conflict – an arrangement that has increasingly chafed Korean pride and sovereignty aspirations.

Trump's America First Meets Korean Ambition

The Pentagon's 2026 strategy reflects Donald Trump's America First doctrine, which demands allies shoulder greater defense burdens. But unlike other allies who've bristled at such pressure, South Korea appears ready to embrace the challenge.

This represents a fascinating convergence of American retrenchment and Korean ambition. While Trump seeks to reduce overseas commitments, Seoul has been building indigenous defense capabilities for years – from advanced fighter jets to sophisticated missile systems, including the recently deployed "monster" Hyunmoo-5 missile.

The shift also reflects changing threat perceptions. North Korea's nuclear program has advanced dramatically, but so has South Korea's ability to respond independently. Seoul's defense industry has emerged as a global player, exporting weapons to Poland, Australia, and other nations seeking alternatives to traditional suppliers.

What This Means for Regional Security

For regional security dynamics, this transition raises complex questions. A more self-reliant South Korea could provide greater stability – or potentially destabilize the careful balance that has maintained peace for seven decades.

China likely views this development with mixed feelings. A reduced U.S. military presence might seem appealing, but a more militarily capable and independent South Korea could prove more unpredictable than one constrained by alliance obligations.

Japan faces perhaps the most complex calculations. Korean military independence could reduce Tokyo's own defense burdens, but it might also complicate trilateral cooperation that has grown stronger under shared U.S. leadership.

The Economic Dimension

Lee's emphasis on connecting "robust self-reliant defense" to "sustainable economic growth" reveals another layer of Korean thinking. Defense spending increasingly drives technological innovation, from semiconductors to artificial intelligence. South Korea's defense buildup isn't just about security – it's about industrial policy.

The country's defense exports have surged, generating revenue while reducing per-unit costs for domestic procurement. This creates a virtuous cycle where military independence becomes economically self-reinforcing.