From the late 1940s until the 1970s the United States deployed a considerable arsenal of nuclear weapons outside of the continental United States, or CONUS, in Pentagon jargon.

American nuclear weapons were hosted in 27 different countries. In NATO Europe 7,000 US nuclear weapons were positioned in several countries and they remain in the UK, Belgium, Germany, Greece, Italy, the Netherlands and Turkey.

Today, the US has hardly any tactical nuclear capability in North and East Asia and its regional bases in South Korea, Japan, Okinawa and Guam are vulnerable to Chinese missiles and nuclear-capable long-range bombers.

So will the US return tactical nuclear weapons to the Pacific as tensions rise with China? Much has changed in the global power balance as the US posture on nuclear weapons evolved.

Germany, which was considered during the Cold War as the prime target of the USSR and its Warsaw Pact allies, had 21 different types of US nuclear weapons there to deter Moscow.  

In Asia, the US had roughly 2,000 land-based nuclear weapons in South Korea, Japan, Okinawa and Taiwan where some 200 nuclear weapons were positioned. In addition, the US Navy had another 3,000 nuclear weapons of different types on aircraft carriers, cruisers, destroyers, frigates and attack submarines.

Guam was loaded up with 20 different nuclear weapons types while Okinawa had 19. All of these weapons were designed to deter China and North Korea. And most of these weapons are now gone.

Before China had a significant nuclear capability, the US at least twice threatened to use atomic weapons against North Korea and China, the first in the Korean War and the other when China threatened to take over Quemoy (Jinmen) and Matsu (Mazu) islands as a prelude to invading Taiwan. 

In the first case, president Harry Truman rejected advice he was getting from his Air Force commanders and did not approve strikes against North Korea. 

A missile test fire from a US nuclear submarine. Image: AFP

In the second, president Dwight Eisenhower authorized preparations to use atomic weapons against China. The initial US Air Force plan was to drop between 10 and 15 atomic weapons on “selected fields in the vicinity of Amoy (Xiamen).”

The Air Force plan of attack would have used bombers stationed either at Kadena Air Base in Okinawa or Anderson Air Base on Guam. The likely nuclear bomb would have been the MK-6 and the likely delivery system a strategic bomber. 

The US Air Force had a considerable selection of bombers, including the B-29 that was used in the Hiroshima and Nagasaki atomic bombings, the B-36 Peacemaker, the B-47 Stratojet and the B-50 Superfortress. 

The MK-6 (or Mark VI) was manufactured in large numbers between 1951 and 1955 and remained in service until 1962. It weighed about 3,629 kilograms (8,000 lbs) and was based on the plutonium fission bomb that was dropped on Nagasaki. 

The typical yield of the bomb was 26 kilotons –but versions of the MK-6 ranged up to 160 kilotons. (By comparison, the Nagasaki “Fat Man” bomb had a kiloton range of 18 to 23).

When Eisenhower was told that the Air Force had readied a second strike by putting B-47 nuclear bombers on alert at Anderson Air Force Base on Guam, Eisenhower understood that even a first strike of 10 to 15 atomic weapons might not stop the Chinese. He looked for an alternative and chose negotiations to defuse the situation.

The US not only had gravity bombs in its arsenal. Among the many types of tactical nuclear weapons were cruise missiles and ground to air/surface to surface rockets. Among the former was the MGM Matador, a jet-powered cruise missile with a range of 250 miles that was later extended. 

It carried a W-5 atomic warhead, the predecessor of the MK-6 with about the same yield profile. The Nike Hercules was a two-stage weapon primarily designed as a ground-to-air weapon intended to kill Soviet bombers. It was typically fitted with a low-yield nuclear warhead. 

However, the Nike Hercules could also serve as a surface to surface theater nuclear weapon with a range of 90 miles (140 kilometers). In a surface-to-surface configuration, the Nike Hercules could carry a 28 kiloton atomic weapon.

The Nike Hercules was originally designed to kill Soviet bombers. Image: Wikipedia

While the US fielded a huge arsenal of nuclear weapons in both the Asian and NATO theaters, the US approach was different in Europe and Asia. In Europe, the US was willing to enter into nuclear sharing and tasking agreements through NATO with Germany, the UK, Italy and Turkey, meaning that the European partner countries would be tasked to deliver US nuclear weapons on targets in case of a major Warsaw Pact attack.

The sharing arrangement extended, in the case of the UK, to ballistic missile attack submarines, but not until 1981 when the Trident program got US approval. Otherwise, the US consistently opposed “local” or independent development of nuclear weapons in Europe, thwarting efforts by Italy and Germany.

In Asia, the US worked to kill nuclear weapons programs in South Korea and Taiwan. In the Korean case, this included blocking suppliers from Canada, France and Germany. It also included shutting down South Korean access to Nike Hercules technology, which the South Koreans wanted as a delivery system by extending the missile range.  

The case of Japan was and remains rather more complicated because Japan developed both a significant nuclear power industry producing large amounts of plutonium and a space program with long range rockets. 

However, while there have been from time to time voices in Japan suggesting the time had come for Japan to manufacture and deploy nuclear weapons, this has not happened. As a victim of US atomic weapons, Japan has a strong bias against nuclear weapons.

The US kept its nuclear weapons in South Korea for 33 years (1958 to 1991). On Okinawa, the US stationed nuclear weapons between 1957 and 1967 (and perhaps earlier). When Okinawa was returned to Japanese control in 1972, the US removed all its nuclear weapons. In the same year, the US removed some 200 US nuclear weapons from Taiwan.

The situation in Guam is more cloudy. Guam has gone through a transition where it no longer hosts strategic bombers full time — instead, it gets rotations of strategic bombers coming from the US (CONUS).

The US has three strategic bombing systems – the venerable B-52, the B-1 “bone” and the B-2 stealth bomber. The B-1 is no longer certified for nuclear weapons. Gravity nuclear bombs have also been removed from the B-52, leaving only the B-2 stealth bomber as a platform for nuclear weapon delivery.

The US Air Force is developing a Long-Range Standoff Weapon (LRSO) for the B-52, but the LRSO won’t enter service until 2030, if the program is continued. While the US is well along on developing a new strategic bomber, the B-21, it won’t enter service until 2026-27 at the earliest. 

A gas-masked South Korean environmental activist holds an anti-nuclear picket in front of Taiwanese and North Korean flags placed by the protestors in Seoul 16 July. The demonstration was to protest against Taiwan's plan to ship nuclear waste to North Korea for disposal. AFP  PHOTO / AFP PHOTO / CHOO YOUN-KONG
A gas-masked South Korean activist holds an anti-nuclear picket in front of Taiwanese and North Korean flags. Photo: AFP/Choo Youn-Kong

The F-15 and F-16 have been certified to carry nuclear gravity bombs, but the US is converting to the B-61-12 gravity bomb that so far has only been certified on the F-15E. The F-35 stealth jet is not yet certified and may never be authorized for a nuclear mission.

In a nutshell, the US’ nuclear tactical capability has been significantly downsized or nearly eliminated, even while China has built a significant arsenal of missiles and aircraft that can deliver nuclear weapons.  

In NATO, this has meant that some nations, Germany and Turkey in particular, no longer fly nuclear-capable fighter aircraft. And it has created peculiar situations such as the US base at Incirlik, Turkey that stores (now mostly obsolete) B-61 gravity bombs. There are no nuclear-certified US aircraft that operate at the base.

In the Northern and Eastern Pacific, the US does not have any tactical nuclear capability. Even in Guam there are no aircraft that could be launched to hit targets in North Korea or China using nuclear weapons.

The key question is whether the US virtual elimination of tactical nuclear weapons in North and East Asia is a good thing considering China’s military buildup and nuclear attack capability as well as North Korea’s expanding nuclear arsenal. 

The US plays the role of supporting its allies and friends and resisting aggression in the region, yet it is less able to credibly deter an adversary that outguns the US and its allies and friends and can attack at will US bases in the region including Guam.

Moreover, the US no longer has much of a tactical nuclear weapons arsenal that can act as a deterrent to conflict in North and East Asia.

Without a meaningful change in direction in countering potential nuclear-armed adversaries such as China and North Korea, American assurances to maintain the balance of power and protect allies and friends seem more a forlorn hope than a guarantee.