Nuclear-armed sub’s appearance a deterrent to North Korea

Reuters

When a United States ballistic missile submarine surfaced for a rare visit to South Korea in mid-July 2023, it was a blunt reminder that Washington has nuclear-tipped missiles deployed within striking distance of North Korea, analysts said.

Some analysts say having undersea nuclear weapons off the Korean Peninsula is a potentially stronger deterrent to the North than installing them in South Korea, as Washington previously did.

“Deterrence is strengthened when the location of American strategic assets is unknown to the adversary as long as the adversary knows that these weapons exist,” said Duyeon Kim of the Center for a New American Security.

The USS Kentucky, an Ohio-class submarine, arrived in Busan, South Korea, on July 18 and departed three days later, said a source with knowledge of its movements. A second U.S. submarine, the USS Annapolis, arrived at a naval base on South Korea’s Jeju island on July 24. The Annapolis is not nuclear armed.

The appearances got attention in North Korea, whose growing nuclear threats prompted the show of Republic of Korea-U.S. cooperation. North Korea’s defense minister threatened that the USS Kentucky’s presence could justify the North using its nuclear weapons.

Backing up its promise to defend the South, Washington has stepped up displays of nuclear force and created a new nuclear consultative group for contingency planning.

The People’s Republic of China, the North’s most important ally, has accused the U.S. of increasing tension in the region with its military deployments.

U.S submarines armed with ballistic missiles seldom make public stops in foreign ports. Relying on secrecy and stealth, they are the most survivable delivery platform of all U.S. nuclear weapons, capable of nuclear retaliation if an enemy strikes first, said Vann Van Diepen, a former U.S. government weapons expert who works with the 38 North project that monitors North Korea.

The U.S. Navy fields 14 such submarines. An Ohio-class submarine carries 20 Trident II D5 missiles, each of which can deliver up to eight nuclear warheads to targets as distant as 12,000 kilometers.

North Korea has an aging, primarily defensive submarine force but wants to develop an arsenal of missile submarines.

It has conducted launches from a test submarine and has sought to build a conventionally powered missile submarine since at least 2016, Van Diepen said.

“De-facto nuclear sharing between the United States and South Korea is happening,” said Choi Il, a retired South Korean submarine captain.

“Kentucky’s port call in Busan is telling us that the submarine has already been operating in waters around the Korean peninsula and even after it leaves Busan, the U.S. nuclear asset is always deployed in waters nearby.”