Does nuclear deterrence work? And, assuming that it does, is it needed by Japan and South Korea? Perhaps the Israeli example offers some guidance.
Since the mid-1960s, Israel has pursued a nuclear program and today is credited with having a significant nuclear arsenal, although little is actually known about it. According to various reports, Israel has some 80 or more nuclear weapons, although one report, quoting Colin Powell, puts the number at 200. It has medium- to long-range delivery systems in the form of ballistic missiles (Jericho 2 and Jericho 3) and submarine-launched cruise missiles, as well as bomber-launched weapons (originally the F-4 but today most likely the F-15). In short Israel has a nuclear triad not dissimilar to that of the United States.
Ironically, Israel’s conventional and nuclear might has proven important not only in its own defense, but in convincing some Arab countries surrounding it to look for accommodation and even working alliances. If recent reports are true, even Saudi Arabia is looking at Israel to help protect the Kingdom, which helps explain the apparent “secret” visit to Israel of Mohammed Bin Salman, the country’s Crown Prince, First Deputy Prime Minister and Minister of Defense. Salman’s preoccupation is with the growing Iranian domination of Iraq, Lebanon and Syria (partly supported in Iraq by the United States and in Syria by Russia). And he is worried that Iran may only be a screwdriver away from a nuclear weapon, taking into account cooperation between Iran and North Korea on missiles and weapons of mass destruction.
Saudi Arabia needs Israel, because Israel is the only local nuclear power that can offset the Iranian threat. And though Israel is likely only to defend itself, the Saudis must find a way for Israel to expand the scope of its deterrent. It is possible that such an arrangement could be on the cards if Saudi Arabia concludes a peace agreement with Israel.
For Japan and South Korea, the problem is different. Both appear to lack any nuclear deterrent and are relying on the United States for security. Both are anti-nuclear, although Korea’s defense minister has apparently suggested inviting the US to return American nuclear weapons to South Korean territory. It is unlikely that will happen because the ruling party will be under very heavy political pressure to resist that option.
In Israel’s case, the decision to move ahead on nuclear weapons rested on a secret agreement with the United States that appears to have been worked out in September 1969 when then-Prime Minister Golda Meir visited Washington and met with President Nixon and his National Security Advisor, Henry Kissinger. The deal allowed Israel to work secretly at its nuclear reactor site in Dimona to develop its deterrent weapons. There may have been other related cooperation between the US and Israel, especially after the 1973 Yom Kippur war when Israel apparently mobilized its nuclear weapons in response to a threatened Soviet intervention and CIA reports that the USSR had shipped nuclear weapons to Egypt on two ships. The US also declared a DEFCON 3 state of alert.
Over the years, Israel has adopted a policy of nuclear ambivalence: it will not say whether or not it has nuclear weapons, and it will also not allow inspection of its Dimona nuclear reactor complex or sign the Nuclear Non-Proliferation Treaty (NPT). The NPT is a problem for Japan and South Korea because both are signatories, although Iran, Iraq and Syria are as well. The truth is that when a country thinks it needs nuclear weapons, arms limitation agreements are largely meaningless.
Japan is almost immediately capable of producing nuclear weapons because it has large stockpiles of plutonium and a long history with nuclear technology stretching back almost a century. Japan also has a strong space program, meaning it has the ability to rapidly convert its heavy space launch vehicles into nuclear delivery systems. Could Japan secretly develop a powerful nuclear deterrent? There is no doubt that it is capable of weapons development, but it is unlikely to remain a secret. Japan lacks the sort of censorship laws that could prevent disclosure.
It can’t be ruled out that both Japan and South Korea already have nuclear weapons but have never tested them. While testing is essential to make sure the designs are reliable, it is useful to remember that the atomic weapon dropped on Hiroshima was never tested
South Korea also has a mature nuclear industry, with four major nuclear reactor sites, each having at least four reactors. Twenty two percent of South Korea’s electrical power is nuclear. The country also has a deployed missile capability, including the Hyunmoo 2C, which is a ballistic missile with an 800 km (almost 500 mile) range, and the Hyunmoo 3-B, which is a cruise missile modeled on the US Tomahawk, with a range of 1,500 km (932 miles) that is being extended to 3,000 km (1,864 miles).
Hyunmoo means “Guardian of the Northern Skies,” and the latest version is capable of carrying a nuclear warhead and covering all of North Korea. Korea is also enriching uranium using a laser enrichment method, which it belatedly reported to the IAEA. The speculation is that South Korea could have nuclear weapons in one to three years, and while this might present political problems, the threat from the North may lead to a nuclear weapon capability sooner rather than later. Indeed, South Korea may have to choose between relying on the United States, which is controversial in Korean leftist circles, or fielding its own.
It can’t be ruled out that both Japan and South Korea already have nuclear weapons but have never tested them. While testing is essential to make sure the designs are reliable, it is useful to remember that the atomic weapon dropped on Hiroshima was never tested. By the same token, Israel likely has never tested a nuclear device – although it was suspected of doing so once, almost forty years ago. Today, nuclear weapons tests can be simulated on supercomputers. Japan and Korea have those and working out weapons sequences and reentry issues is well within their capabilities.
Given the challenge from North Korea, it is unlikely that either South Korea or Japan will sit idly by or depend solely on the United States. More likely, each will secretly develop nuclear weapons following the Israeli model, if they have not already done so.