This naturally gives both Koreas a maritime outlook, but also makes them both vulnerable to military action from the sea. Most major cities and towns are located on the country’s west and east coasts, and no point in the entire country is more than 130 miles from the sea. In the event of war with North Korea, the United States Navy will be particularly useful in—ideally—bringing war to a swift conclusion. Here are five U.S. Navy weapons that would be indispensable in such a conflict.
1 - Avenger-class Minesweepers
North Korea, having faced a quick reversal of fortune after the amphibious invasion at Inchon, is well aware of the threat of a seaborne attack. Sea mines are a cheap and effective means of keeping hostile navies away from friendly shorelines—in 1988, the frigate USS Samuel B. Roberts hit an Iranian mine in the Persian Gulf , while in the 1991 Gulf War the cruiser USS Princeton and amphibious assault ship USS Tripoli were also damaged by sea mines .
American and South Korean forces can expect to face North Korean mines guarding ports, harbors, and important waterways. The powerful U.S. Seventh Fleet not only includes an aircraft carrier and amphibious assault ships but four minesweepers of the Avenger class : USS Patriot, USS Pioneer, USS Warrior and USS Chief. Those ships, along with their South Korean—and perhaps even Japanese—counterparts will need to sweep littoral waters before amphibious ships laden with Marines can approach North Korea’s shoreline. For want of a minesweeper, multibillion-dollar ships vital to an allied attack or counterattack could be stranded at sea, unable to contribute to the war effort.
2 - Wasp-class Amphibious Assault Ships
Once war begins the only reasonable outcome will be the collapse of the Kim regime. This makes rapid attack and destruction of the North Korean armed forces a maximum priority. In order to facilitate regime collapse, the U.S. Navy will large, capable amphibious forces to not only mount but sustain a seaborne invasion.
The Wasp-class amphibious assault ships  are in many ways the ultimate amphibious platform. More than eight hundred feet long, each can carry up to two thousand Marines and their equipment, including tanks, light armored vehicles and artillery. The ships can land ground forces by air via MV-22 Osprey and CH-53E Sea Stallion transports or hovercraft operating from the ship’s floodable well deck. A Wasp-class ship can even provide its own air support in the form of AV-8B Harriers or F-35B Joint Strike Fighters. The ships also have extensive command-and-control facilities for directing an assault and medical facilities for treating the wounded.
3 - Arleigh Burke–class Destroyers
The workhorse surface combatants of the next Korean War are the Arleigh Burke–class guided-missile destroyers. First introduced in the 1980s, the Burkes are among the most versatile ships in their weight class, capable of taking on everything from naval gunfire support to ballistic missile defense.
Arleigh Burke destroyers  can defend locations such as Guam or U.S. bases in Japan from aircraft and ballistic missiles, bombard enemy shore positions with their Mark 45 five-inch guns, protection surface ships including aircraft carriers and an amphibious force with the Aegis combat system, and hunt down and sink the Korean People’s Navy’s outdated surface and submarine forces. The U.S. Seventh Fleet is typically home to seven Burke-class destroyers, but two, John S. McCain and Fitzgerald, are out of action after sustaining damage in accidents with commercial merchantmen.
4 - Ohio-class Guided-Missile Submarines
During the early 2000s, arms control agreements made it possible for the U.S. to remove several Ohio-class ballistic-missile submarines from the nuclear deterrent force. Rather than retire the hulls, four of the boats were converted to carry Tomahawk cruise missiles  instead of Trident D-5 submarine-launched ballistic missiles.
Each of the four converted boats can carry up to 154 Tomahawk missiles. Low flying and precision guided, Tomahawks have been the first wave of U.S.-led attacks since the 1991 Persian Gulf War, and were used most recently in the attack on the Syrian airfield at Shayrat . A war in Korea would be no different, with Tomahawks striking North Korean air force bases, command-and-control centers, air-defense sites and other facilities. The Ohio-class submarines are also capable of transporting Navy SEALs, bringing them and their Seal Delivery Vehicle mini-submersibles near enemy coastlines for infiltration purposes.
5 - Nimitz-class Aircraft Carrier
For more than seventy years, aircraft carriers and their air wings are some of the most versatile naval platforms around. Carriers filled an important role in the Korean War, providing invulnerable platforms for air superiority, strike and ground-attack missions that the North Koreans—and later the Chinese—could not touch. Sitting a healthy distance away from shore-based guns, aircraft carriers could launch their planes and strike anywhere in the country.
In the event of Korean War II, the Seventh Fleet’s USS Ronald Reagan , as well as any other carrier operating in the area, will fulfill a similar role. With two major U.S. Air Force bases in South Korea to cover near the DMZ, the U.S. Navy’s flattops and their four squadrons of Hornet and Super Hornet fighters can concentrate on targets farther north, or in support of a seaborne invasion. Highly mobile and capable of relocating hundreds of miles a day, they can adjust their position to support an advance by Army and Marine units across the country.
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 .