In a move to significantly increase its militarization and preparations for war, South Korea intends to construct its own nuclear-powered submarines. US President Trump gave his support for the plan during his summit last week with South Korean President Lee Jae-myung.

The acquisition of nuclear-powered submarines is a highly provocative move not only due to the vessel’s capabilities in warfare, but also in regards to possession of the nuclear fuel required, which is weapons-grade, highly enriched uranium. To date, only countries that also possess nuclear weapons have built nuclear-powered vessels.

To obtain the uranium necessary, Lee Jae-myung on October 29 requested Trump “make a decision to allow us to receive fuel for nuclear-propelled submarines.” Under a 2015 pact with the US, South Korea is banned from enriching uranium beyond 20 percent, and this only for research purposes. Lee also asked that restrictions on Seoul’s ability to enrich uranium or reprocess spent nuclear fuel be eased.

The following day, Trump wrote on his Truth Social platform, “Our Military Alliance is stronger than ever before and, based on that, I have given [South Korea] approval to build a Nuclear Powered Submarine, rather than the old fashioned, and far less nimble diesel powered submarines that they have now.”

At least some of the submarines will be built in the US, at the Hanhwa Philly Shipyard in Philadelphia, according to Trump, though it currently lacks the necessary facilities. The shipyard is owned by South Korea’s Hanhwa Ocean, which is expected to play a central role in Trump’s “Make American Shipbuilding Great Again” program, in which South Korea will help train, construct and modernize US shipyards.

The exact details of the plan or how South Korea will obtain the enriched uranium for the fuel have yet to be elaborated. However, Seoul plans to build at minimum four nuclear-powered submarines within the next ten years, though experts have questioned the feasibility of this. The South Korean navy is calling for vessels of 5,000 tons or higher, which would have ten or more vertical launching system (VLS) tubes to fire missiles. Currently, the largest submarine in the fleet is 3,600 tons.

Lee tried to downplay his government’s request while also making clear this is in line with Washington’s build up to war with China. Lee claimed, “We are not proposing to build submarines armed with nuclear weapons; rather, diesel submarines have inferior submerged endurance, which limits our ability to track North Korean or Chinese submarines.”

Lee stated that South Korea’s possession of a nuclear-powered submarine fleet would “ease the burden on US forces.” This is taking place largely behind the backs of the population while Lee came to office in June falsely posturing as an opponent of war.

South Korea has long sought nuclear-powered submarines. The vessels have several advantages over conventional diesel engines, which include greater speeds, having a practically unlimited range, and remaining submerged for far longer periods.

South Korea’s Defense Minister An Gyu-baek stated on Wednesday that the submarines should be built domestically. He told a National Assembly defense committee, “We have accumulated technologies and studied know-how over the past 30 years on nuclear-powered submarines, so I think it is reasonable [to build them in South Korea].”

This raises a number of questions. Constructing nuclear-powered vessels is not banned by the Nuclear Non-Proliferation Treaty, which South Korea became a party to in 1975. However, obtaining the highly enriched uranium necessary to power the vessels is also a major step towards building a nuclear weapon. Even if the US provides the fuel without Seoul’s involvement in the enrichment process, it signifies a further chipping away at restrictions on the latter’s nuclear weapon ambitions.

Producing nuclear energy or weapons requires the uranium-235 isotope. In nature, more than 99 percent of uranium ore is uranium-238 with uranium-235 making up only 0.72 percent. The ore must be “enriched” to isolate the latter. In civilian power plants, this nuclear material is enriched to only three to five percent. As the level of enrichment rises, the ability to increase to higher levels becomes easier.

That Seoul might build nuclear weapons is not out of the question. In the 1970s under dictator Park Chung-hee, South Korea initiated a nuclear weapons program, which the US attempted to force Seoul to shut down through a treaty when it was discovered, a precursor to the 2015 deal. Though Seoul agreed publicly, its nuclear experiments continued for decades in secret under both right-wing and Democratic Party governments.

More recently, in January 2023, former president Yoon Suk-yeol declared that South Korea would consider developing its own nuclear weapons. This led in April of that year to the establishment of the so-called Nuclear Consultative Group (NCG), modeled on a similar body in NATO dealing with nuclear matters. The NCG gives Seoul a greater say in planning the use of nuclear weapons as well as training in their use.

As a result, the targets of US imperialism like China and Russia will have no choice but to consider that Seoul is pursuing a nuclear weapon in secret or could do so in the future. It also exposes the hypocrisy of Washington and Seoul in regards to North Korea, and the claims that the two allies are working to “denuclearize” the Korean Peninsula.

Other countries in the region are also pursuing the acquisition of nuclear-powered submarines. Australia plans to acquire the vessels through the AUKUS alliance, which includes the US and the United Kingdom. In Japan, the coalition deal of the new far-right government in Tokyo between the Liberal Democratic Party and Nippon Ishin no Kai calls for, among other remilitarization demands, developing submarines with “next-generation propulsion systems,” a euphemism for nuclear-powered.

This will be compounded by the fact that Trump also announced last week just prior to a summit with Chinese President Xi Jinping plans to resume nuclear weapon testing for the first time since Washington imposed a unilateral ban in 1992. All of this will only further increase tensions and a nuclear arms race in the Indo-Pacific.