The Republic of Korea Navy's 3,000-ton submarine Anmu departs from a naval base in Busan, June 11, to take part in a drill. Courtesy of ROK Navy

Recent remarks by the chief of the U.S. Indo-Pacific Command regarding the potential introduction of nuclear-powered submarines in South Korea could signify a subtle yet significant shift in the U.S.' stance, according to observers, Monday.

While this latest development could amplify calls for Seoul to acquire nuclear weapons, some military experts remain skeptical about whether the introduction of nuclear submarines is a feasible idea given the financial and diplomatic hurdles involved.

"From the perspective of submarine warfare, it is crucial for allies and partners to find the most efficient and effective ways to combine our capabilities to defend our alliances and partnerships," Commander Adm. Samuel Paparo said during an interview with Korean reporters at Hickam Air Force Base in Hawaii on Thursday.

The Korean presidential office disclosed the full transcript of Paparo's interview Sunday.

"If operational analysis leads us to conclude that, then we can consider moving forward at a later date. We should approach this as equals and progress accordingly," Paparo said, responding to inquiries about the increasing calls within South Korea for the nation to possess its own nuclear arms, including nuclear-powered submarines.

Cheong Seong-chang, director of the Center for Korean Peninsula Strategy at the Seoul-based Sejong Institute, viewed this as a subtle change in the U.S. stance on Seoul obtaining its own nuclear weapons.

"Until now, the United States has sternly opposed South Korea possessing nuclear submarines. This marks the first time a current key military official has publicly shown a somewhat positive stance on the matter," Cheong said.

The expert suggested that Paparo's remarks could signal that U.S. officials may be starting to recognize the potential strategic benefits of South Korea having nuclear subs.

"From the U.S.' perspective, the introduction of South Korean nuclear submarines would not only serve as a counterbalance to the increasing nuclear threats from North Korea that could target the U.S. mainland but also to China's expanding naval capabilities," Cheong said.

Since North Korea claimed to have launched its first-ever operational submarine, allegedly capable of launching nuclear-capable ballistic missiles, in September 2023, there have been growing calls for the South to bolster its naval capabilities, including nuclear options.

"We cannot rely solely on aircraft carriers to deter North Korea's submarine threats, nor can conventional diesel submarines counter them effectively. Hence, nuclear submarines, with their higher speeds and enhanced stealth capabilities, are essential," Cheong stressed.

A newly built "tactical nuclear attack submarine" is seen at Sinpo Shipyard in South Hamgyong Province, North Korea, Sept. 6, 2023, in this photo released two days later by the North's state media Korean Central News Agency. Yonhap

On the other hand, Kim Dae-young, a military expert, dismissed Paparo's remarks as mere rhetoric to mitigate the growing calls in South Korea for nuclear weapons.

"The U.S. is unlikely to change its fundamental stance," Kim said, suggesting that Paparo's comments on "operational analysis" indicate that the U.S. is reluctant to commit to another nuclear partnership after the one with Australia.

Under the AUKUS security partnership signed in 2021, the U.S. will sell Australia three to five Virginia-class attack submarines starting in the early 2030s.

AUKUS is an Indo-Pacific trilateral security partnership between the U.S., the United Kingdom and Australia.

During the Shangri-La Dialogue security summit in Singapore in May, U.S. Secretary of Defense Lloyd Austin expressed skepticism about Washington assisting Seoul in acquiring nuclear submarines, stating it would be "very, very difficult" for the U.S. to support another nuclear initiative similar to Australia's.

Kim also pointed out that the Republic of Korea Navy would face the substantial costs of acquiring a fleet of nuclear-powered submarines, estimated at a minimum of 2 trillion won ($1.44 billion) per submarine. He argued that this tremendous amount could be better spent bolstering other military capabilities.

"Plus, the Navy, which is struggling with a personnel shortage, would confront significant challenges in recruiting and training nuclear-qualified sailors," he said.

Paparo's remarks came amid increasing calls from conservative politicians advocating for the nation to independently pursue nuclear armament. Last week, the ruling People Power Party (PPP) launched the Mugunghwa Forum, a group of about 20 lawmakers advocating for South Korea to go nuclear.

The forum, chaired by Rep. Yu Yong-weon, a military expert-turned-lawmaker, includes prominent figures such as Rep. Na Kyung-won, a candidate for the PPP's leadership; Rep. Kim Gunn, a former nuclear envoy at the Ministry of Foreign Affairs, and Rep. Lee Jun-seok of the minor Reform Party.