US President Joe Biden (R) shakes hands with Yoon Suk Yeol during the South Korean president's state visit
US President Joe Biden (R) shakes hands with Yoon Suk Yeol during the South Korean president's state visit AFP

A US-South Korean agreement on strengthening deterrence against Pyongyang will discourage Seoul from seeking nuclear weapons, but also highlights the near absence of viable ways to remove the threat of North Korea's arsenal.

For years, the United States and the international community have unsuccessfully pushed for North Korea to give up its weapons, which pose a long-running danger that has encouraged many in the South to believe Seoul needs its own nuclear arms.

Seeking to head off such a move, Washington agreed on Wednesday to deeper cooperation with Seoul on nuclear issues and the regular deployment of strategic assets to South Korea.

President Yoon Suk Yeol, on a state visit to the United States, in turn reaffirmed his country's commitment to non-proliferation.

As a result of the joint agreement, "South Korea is going to be more involved in conversations about the nuclear part of deterrence, not just conventional deterrence," said Naoko Aoki, associate political scientist at the RAND Corporation.

This is "a reflection of the increased concerns and tensions resulting from North Korea's nuclear and missile development," Aoki said, noting that "the geopolitical environment and North Korea's ongoing military modernization plan, among other issues, make it unlikely that North Korea will come to the negotiating table soon."

North Korea has defied years of punishing sanctions to continue work on its banned nuclear and missiles programs, and has shown no signs that it is willing to consider giving up weapons it views as insurance against regime change.

Pyongyang conducted a record-breaking string of sanctions-defying launches this year, including test-firing the country's first solid-fuel ballistic missile -- a key technical breakthrough for North Korean leader Kim Jong Un's military.

Surveys show that a majority of South Koreans believe the country should develop its own nuclear weapons -- an option Yoon had previously hinted Seoul could pursue.

The new agreement "is first and foremost about assuring South Korea and proving to Seoul that the US nuclear umbrella is credible," said Kelsey Hartigan, deputy director of the Project on Nuclear Issues at the Center for Strategic and International Studies, referring to the US commitment to defend its conventionally armed ally.

"The prospects for a breakthrough on denuclearization have always been slim," she said. "The question is not whether North Korea is going to give up its nuclear weapons, it's whether South Korea is going to develop its own in response."

The United States' long-held goal has been the complete denuclearization of the Korean peninsula, and that is unlikely to change.

"I don't see the United States formally walking away from its broader policy position on denuclearization anytime soon," Hartigan said.

Frank Aum, senior expert on Northeast Asia at the US Institute of Peace, warned of a possible North Korean response to the new agreement.

"If we're showing power right now, then it's very likely that North Korea's going to come back and respond with its own demonstration of power. It could be a satellite launch or a seventh nuclear test," Aum said.

"Then South Korea will want to respond again to show that it's responding and at some point we're going to run out of nuclear goodies to give to South Korea."