“This request will bolster our ability to defend our country, paced to the challenge posed by an increasingly aggressive People’s Republic of China,” US Defence Secretary Lloyd Austin said in a statement.

The PDI budget includes money for ballistic missile defence activities that contribute to developing and integrating a joint missile defence system to defend Guam against missile threats, as well as funding for exercises, training and experimentation activities, plus planning and design for military construction investments in the western Pacific.

Austin added that he expected some funding may go towards the construction of new airstrips in the Pacific to avoid an overconcentration of forces.

05:22

Why the South China Sea dispute remains one of the region’s most pressing issues

Why the South China Sea dispute remains one of the region’s most pressing issues

Another major investment in deterrence capabilities included in the budget request was the development of the latest Columbia-class ballistic missile submarine (SSBN), replacing the nearly five-decades-old Ohio-class.

Construction began in 2020 on the first Columbia-class submarine, which is scheduled to enter service in 2031. The second is expected to begin construction this year after the Defence Acquisition Executive’s (DAE) authorisation in September 2023.

The Pentagon allocated US$9.9 billion for the submarine budget, up US$3.7 billion from the US$6.2 billion allocated in 2024. The rise was attributed to “increases for the submarine industrial base and in advance procurement costs for the FY2026 submarine”.

“[The Columbia-class submarines’] defining characteristic will be the ability to launch ballistic nuclear missiles as part of America’s strategic deterrence,” Timothy Heath, a senior international defence researcher at the US-based think tank Rand Corporation, said.

“The new submarine will also feature a quieter electric engine system, an improved nuclear power system that should reduce maintenance downtime and greater overall durability, which should enable each submarine to serve for 42 years.”

The Pentagon, home to the US Defence Department, has requested increased budget for deterrence against China. Photo: Reuters
With the budget request focusing on deterring Chinese military activities, analysts said submarines would become more important in the Indo-Pacific region in the future.

“Equipped with the latest technology, these will be exceptionally difficult to target. Therefore, states in conflict with the United States will be under the continual threat of nuclear attack,” said John Bradford, executive director of the Yokosuka Council on Asia-Pacific Studies and a former US Navy officer.

“China’s advances in undersea warfare are certainly keeping the US engaged with upgrading its own capabilities,” he said. “This upgrade will ensure the status quo nuclear deterrence situation remains in place even as anti-submarine warfare technology improves.”

Collin Koh, a senior fellow at the S. Rajaratnam School of International Studies in Singapore, said Washington’s investment in the Columbia-class submarines comes from an “urgent need” to replace the ageing Ohio-class SSBN – with the understanding that a sea-based deterrent is more secure for a second strike than other “nuclear triads” such as intercontinental ballistic missiles or strategic bombers.

“It isn’t [only] designed for the Pacific,” Koh said. “But I think overall, there are broader concerns in the US about the ongoing strategic stability with … China and Russia because both of these so-called rival countries are also building up their own nuclear capability.”

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Beijing has also recently been focusing on increasing its submarine capabilities. In August last year, a report from the China Maritime Studies Institute of the US Naval War College said China’s latest Type 096 SSBN will be quieter and have significant improvements over its predecessor, posing “profound implications for US undersea security”.

In December, Beijing appointed submarine expert Hu Zhongming as the new PLA Navy commander.

Brian Hart, a fellow with the China Power Project at the Washington-based think tank Centre for Strategic and International Studies, said the US submarines still have a “major qualitative advantage” over China. They are all nuclear-powered, compared to China’s diesel-powered submarines, and the US submarines have a longer history of conducting operations globally.

However, he said Beijing is modernising “virtually all areas of its navy”. The PLA has made submarines a priority, steadily adding nuclear-powered attack submarines to its fleets, including six SSBNs that provide credible sea-based deterrence.

“In East Asia, China has a home-field advantage. Most of its submarines do not venture far from China’s own shores while US submarine forces are globally deployed,” Hart said.

03:03

Taiwan simulates attack from mainland China as island’s military conscripts begin extended service

Taiwan simulates attack from mainland China as island’s military conscripts begin extended service

“That too is changing, though, as China is increasingly looking to field its submarines farther from China, in places like the Indian Ocean,” he said. “Its force of SSBNs is particularly important. China is undertaking an unprecedented and rapid expansion of its nuclear forces.”

Heath, from the Rand Corporation, stressed that “submarine operations are important in the Indo-Pacific just as they are for all naval operations” due to their ability to fire anti-ship cruise and ballistic missiles. He said both the US and China are expected to continue investment in their submarine capabilities.

“Modern anti-ship missiles have rendered large surface ships, such as aircraft carriers, extremely vulnerable. Submarines are especially effective at sinking enemy ships, and thus the US Navy could be expected to rely heavily on submarines to fight a Chinese invasion of Taiwan,” he said.
Meanwhile Koh, from the S. Rajaratnam School of International Studies, said the “cat and mouse game” is likely to persist between the undersea forces of China and the US, and Washington’s enhancement of its allies and partners, such as Aukus and its trilateral ties with Tokyo and Seoul.

“The problem is that in the region, we don’t have any mechanism that can, in a way, forestall such an eventuality,” Koh said. “So I think we might potentially see the risk of the sea encounters and the sea incidents because of that.”