Key point: Seoul takes its national security very seriously.
In modern Korea’s relatively short history, amphibious warfare has played a key and pivotal role. The United Nations essentially liberated South Korea from invasion with a single amphibious stroke, and the country has maintained a large and powerful Marine Corps ever since. Now, a new generation of South Korean amphibious naval forces means the country can ponder taking the offensive during wartime, not only blunting an invasion but upending the Kim family’s dynastic hold on North Korea.
Korea’s peninsular nature means that the ocean is never far away from residents of both countries. It also means that armies fighting on the peninsula, friendly or not, run lines of communication and supply that are constantly in danger of being severed from the sea. Gen. Douglas MacArthur, well aware that the invading Korean People’s Army was reliant on increasingly tenuous supply lines as it inched south, planned and oversaw a successful amphibious assault at the port of Inchon. The result was an abrupt reversal of fortune for a KPA on the brink of victory, with the shattered remnants of Kim Il-sung’s army racing north to avoid entrapment and annihilation.
Korea, just 160 miles wide and mountainous, doesn’t leave much room for maneuver—that is, unless you count the coastline: the North and South have more than three thousand miles of coastline combined. In any future Korean war, amphibious operations will help avoid costly wars of attrition, avoiding force-on-force fights to instead focus force on an enemy’s center of gravity—like Seoul or Pyongyang.
Under the mentorship of the U.S. Marine Corps, South Korea has maintained one of the largest marine forces in the world. As one USMC colonel put it during the Vietnam War, which saw a brigade’s worth of South Korean marines (and their U.S.-trained officers) sent to Southeast Asia, “We taught them everything we know, and now they know it better than us.” Today, the Republic of Korea Marine Corps (ROKMC) consists of twenty-nine thousand marines organized into two divisions and a brigade.
In past years, the ROKMC has operated as a theater reserve, capable of rapidly reinforcing areas where invading North Korean forces might stage a breakthrough. This could be accomplished by moving troops over land, but it could also be done by sea: in 1975, the ROK Navy had twenty landing ships, including eight tank landing ships, and sixty other amphibious craft. If necessary, the ROKMC could stage its own, smaller-scale version of Inchon, though staging an attack into North Korea was not yet feasible.
After the end of the Cold War and the abandonment of North Korea by its Soviet ally, contingency plans involving the ROKMC began taking a more audacious tone. OPLAN 5027-94, one of the Pentagon’s contingency plans for the Korean Peninsula, envisioned a U.S. and South Korean amphibious landing at Wonsan to make an end-run on Pyongyang. The ROKMC would be used not just to defend South Korea, but to destroy the North Korean government.
North Korea’s development of nuclear weapons has changed the rules of war. No longer can U.S. and South Korean forces wear down their KPA counterparts with firepower, waiting for the ill-supplied, ill-fed and ill-equipped army to disintegrate under the hammer blows of U.S. air power. Now forces must stay mobile, to avoid tactical nuclear strikes, and seek a rapid capitulation of the North Korean government before it can authorize the use of nuclear weapons. A future war on the Korean Peninsula will be a race against time.
This new strategy requires even more of the ROKMC. The new plan is to ROK marine and naval forces to directly invade Pyongyang from the sea, killing or capturing the regime’s leadership before it can use nukes. Towards this end, the Marine Corps has established a new brigade-sized unit code-named “Spartan 3000,” whose mission is the destruction of “key military facilities in the North’s rear during contingencies.” This almost certainly sounds like operations in and around Pyongyang. The brigade will be able to deploy on just a day’s notice from its base at Pohang, far from the demilitarized zone.
Supporting the ROKMC and the new “Spartan” unit will be South Korea’s sealift forces, the flagship of which is the landing platform, helicopter ROKS Dokdo. With a full-length flight deck, island and well deck, ROKS Dokdo is similar in appearance and mission to the Wasp-class landing helicopter-dock ships of the U.S. Navy. Six hundred sixty feet long and weighing nineteen thousand tons fully loaded, Dokdo can carry up to seven hundred ROK Marines and their equipment, including ten trucks, six tanks, six amphibious assault vehicles (AAVs), three artillery pieces, ten Blackhawk-type helicopters and two Korean-made landing hovercraft.
Commissioned with great fanfare in 2007, Dokdo was to be the first of a three-ship class that included a second ship, Marado, and a third possible ship named Baengnyeongdo. Unfortunately, construction never began on the remaining ships and Dokdo risked becoming a white elephant. However, in the spring of 2017 South Korea finally began construction on Marado, and the fate of Baengnyeongdo is uncertain. South Korea also has a fleet of four landing-ship tank vessels, each capable of carrying up to seventeen ROKMC main battle tanks at a time.
Today, a ROKN/ROKMC task force could land a reinforced battalion of marine infantry covered by at least forty tanks. Adding a second Dokdo-class ship would increase that to two battalions. Given that any amphibious landing site won’t be far from ROKMC bases, any landing could be reinforced within a day by a second, equally large force, until enough forces are landed to push inland. ROK Marines could also hitch a ride on the U.S. Navy Seventh Fleet’s amphibious ships based at Sasebo, Japan, making even brigade-sized landings possible.
Wherever in North Korea they land, the ROK Marines are in for a very tough fight. North Korea is heavily garrisoned and home to an army of 1.2 million, with several million more in the reserves and militia. Ideally, a landing would come while the North is fully committed to an attack on the South, leaving little fuel for KPA forces to counterattack a beach landing. The ROK Marines are truly the tip of the spear, and their commitment in wartime will signal the end of the Kim regime.
Kyle Mizokami is a defense and national-security writer based in San Francisco who has appeared in the Diplomat, Foreign Policy, War is Boring and the Daily Beast. In 2009, he cofounded the defense and security blog Japan Security Watch. You can follow him on Twitter: @KyleMizokami. This article first appeared several years ago.