© Reuters. FILE PHOTO: US ballistic missile submarine USS Kentucky is moored at Pusan Naval Base in Pusan, South Korea on July 19, 2023. WOOHAE CHO/Pool via REUTERS/File Photo
Written by Josh Smith
SEOUL (Reuters) – When a US ballistic missile submarine (SSBN) surfaced on a rare visit to South Korea this week, it was a blunt reminder that Washington has always had nuclear-tipped missiles deployed within striking distance of North Korea, analysts said.
Possessing nuclear weapons out of sight in the seas off the Korean peninsula was a potentially stronger deterrent to North Korea, according to some analysts, than installing them in South Korea, as Washington did from 1958 to 1991.
“Placing nuclear weapons abroad and on submarines is actually a stronger deterrent in many ways,” said Doyon Kim of the Center for a New American Security. “Deterrence is enhanced when the location of U.S. strategic assets is unknown to the adversary as long as the adversary knows these weapons are present.”
The SSBN-class ship USS Kentucky Ohio arrived in the southern port of Busan, South Korea, on Tuesday and concluded its visit on Friday, a source familiar with its movements said.
It caught the attention of North Korea.
On Thursday, North Korea’s defense minister said the mere presence of such weapons in South Korea could meet the criteria for North Korea to use its nuclear weapons, and warned the United States against sending more nuclear-capable assets.
Kentucky’s visit was the SSBN’s first to South Korea since the 1980s, and follows a growing debate in recent years about whether the United States should return tactical nuclear weapons to South Korea, or whether it should develop its own.
Reiterating its commitment to the defense of the South, Washington responded by stepping up the show of nuclear force and creating a new war planning group.
China, North Korea’s most important ally, did not comment on the submarine’s visit, but accused the United States of increasing tension in the region through its military deployment.
Always in range
Because American SSBNs rely on secrecy and stealth to ensure their survival and maintain their ability to launch nuclear missiles during war, they rarely make public stops at foreign ports.
SSBNs are the most survivable delivery platform of all US nuclear weapons, essentially ensuring overwhelming nuclear retaliation in the event of an enemy first strike, said Van van Diepen, a former US government weapons expert who works with Project 38 North which monitors North Korea.
US Navy Fields 14 SSBN, often referred to as “Boomers”. The Ohio-class submarine carries 20 Trident II D5 missiles, each of which can deliver up to eight nuclear warheads to targets 12,000 kilometers (7,500 miles) away.
“U.S. SSBNs anywhere from the west coast of the United States westward can strike targets in North Korea,” Van Diepen said. “Therefore, some US SSBNs are within range of North Korea at all times.”
North Korea has a large but aging submarine force with the primary mission of defending its coast, but it is looking to develop its own arsenal of missile submarines.
Van Diepen said it has conducted experimental submarine launches, and has been seeking to build a conventionally powered missile submarine since at least 2016.
But he said the North was still many years away from developing the technical capability to build a nuclear-powered submarine that would give it unlimited range. For now, Van Diepen said, a missile submarine would only marginally supplement North Korea’s burgeoning land-based nuclear force.
“The de facto nuclear weapons sharing between the United States and South Korea is happening right now,” said Choi Il, a retired South Korean submarine captain.
“A Kentucky port call in Busan tells us that the submarine is already operating in the waters around the Korean Peninsula and even after it leaves Busan, US nuclear assets are always deployed in nearby waters.”