ABOUT two weeks ago, this paper's editorial took the United States government to task over its massive nuclear rearmament program and the risk that it poses to the entire world ("The US must halt its nuclear weapons escalation," Oct. 2, 2024). While that was entirely appropriate, the US is, of course, not the world's only nuclear-armed country and, in fact, does not have the largest arsenal. That dubious honor belongs to Russia, which has a stockpile of 5,580 nuclear warheads compared to the US' 5,044. The US, however, currently has slightly more weapons deployed, about 1,770 to Russia's 1,710.
Other nuclear-armed countries besides the US and Russia are the United Kingdom, France, China, India, Pakistan, Israel and North Korea. All of them are in the process of upgrading or expanding their nuclear arsenals, although to what extent is difficult to determine, as no government wants to be too candid about such a sensitive national security matter. In the case of Israel, which is believed to have about 90 nuclear warheads, it has never openly acknowledged their existence. What we know about Israel's nuclear arsenal comes from US intelligence and occasional inadvertent leading comments from Israeli government officials.
For me, researching nuclear weapons goes hand in hand with my constant research on nuclear energy because the latter is an outgrowth of the former. When nuclear fission was discovered, the first thought of physicists was "bomb" (if you saw the movie "Oppenheimer," this moment was brilliantly portrayed), and the second thought, a rather long time after, was "energy." Any country that has a nuclear reactor for electricity generation is a potential nuclear-armed state; most of them do not think of it in those terms, but it is the reality, which is why the Western world gets nervous when a country such as Iran that understands the potential announces its intentions to pursue a nuclear program.
There are currently four nuclear "flashpoints" in the world, and the course of geopolitical events over the past couple of years has, unfortunately, increased the risk that one of these would explode into a nuclear conflict. In order of likelihood, these are:
– North Korea: North Korea has approximately 50 nuclear warheads, and it is estimated that it is producing enough enriched fissile material to build six or seven more a year. Despite energetic work to develop missiles, North Korea's delivery systems are limited. It has a stockpile of intermediate-range missiles that are thought to be nuclear-capable and has one or two long-range intercontinental ballistic missiles (ICBM) capable of reaching targets in most of the US. Obviously, North Korea is working on improving and expanding its missile fleet, but for now, the threat it poses is limited to areas within about 4,000 kilometers.
North Korea has repeatedly threatened to attack the US mainland, and it probably could do so with the aforementioned one or two ICBMs, but US doctrine in case that happens is to turn North Korea into an uninhabitable wasteland of radioactive glass. That is an unlikely scenario. What is a somewhat higher risk, however, is North Korea's potential use of nuclear weapons against South Korea, US bases in the region, possibly even as far away as Guam, or US naval vessels. If there is heightened tension and serious hostilities between the two Koreas, this is a possibility.
– Chinese invasion of Taiwan: China has about 500 nuclear warheads and is rapidly increasing that number. It is believed to only have about two dozen weapons actually deployed in ICBMs or intermediate-range ballistic missiles (IRBM) but is also working on expanding its delivery systems. This effort was set back somewhat by the accidental sinking of its newest ballistic missile submarine back in July.
There are several scenarios in which China might strike with its nuclear weapons in connection with an invasion of Taiwan. One would be to strike at US fleet assets and bases in Japan, South Korea, the Pacific islands, and possibly even the Philippines in order to degrade the effectiveness of the US response to the invasion. Another scenario would be in retaliation for a Taiwanese strike on the Chinese mainland; Taiwan, for example, has a well-designed plan for a long-range missile and strike aircraft attack on the Three Gorges Dam, the destruction of which would cause an environmental disaster of unimaginable scale. The third scenario would be in case of the invasion bogging down before a tough defense by Taiwan and its American allies; China might carry out a nuclear strike, perhaps one missile aimed at one of Taiwan's secondary cities, in order to force a Taiwanese surrender.
– Israeli nuclear attack on Iran: With the conflict in the Middle East evidently spiraling toward an all-out war between Israel and Iran and its various proxies, the potential for a nuclear strike by Israel is also increasing. A scenario in which this becomes possible is if Iran is able to coordinate its clients — its backing of Lebanon's Hezbollah and Yemen's Houthis is well-known, and its support for the various Palestinian factions is suspected — for a major attack on the Israeli homeland and civilian population. In that case, one or more of those Israeli nuclear weapons that do not officially exist could find their way to carefully selected targets in Iran.
– Russian nuclear attack in Ukraine: This is the potential risk that keeps military planners and nuclear forces analysts awake at night. Early in its unprovoked invasion of Ukraine, when things were going very badly for Russia, it was thought that the mostly likely time for a nuclear strike by Russia was when it was being routed; Russia could use one of its tactical nuclear weapons to stop a major Ukrainian attack, for example.
Now, with the war in apparent stalemate and both sides trading territory, the fear is that Vladimir Putin may be more inclined to use one or more nuclear weapons on the back of some Russian success. Ukraine's defense of its homeland has been awe-inspiring in its strength, but in a war of attrition, which is what the conflict has become, Ukraine is at a huge disadvantage. This is not being helped by the senseless handcuffing of Ukraine's forces by prohibitions on using North Atlantic Treaty Organization (NATO)-supplied weapons for strikes deeper into Russia.
If the Russian forces wear down the Ukrainians and begin advancing steadily, Putin might order a nuclear strike on a Ukrainian city in order to force an unconditional surrender. The Russian leader would be gambling that NATO would not respond in kind, and he would almost certainly be right. Not only would this outcome be obviously very bad for Ukraine, but it would also pass all the initiatives for determining the geopolitical direction of Europe into the Russian dictator's hands.
The only way to ensure that scenario doesn't happen is to ensure a decisive victory by Ukraine. Even then, that does not completely rule out the use of nuclear weapons by Russia as a desperate counterpunch in the midst of an overwhelming defeat, but it would not necessarily shake the foundations of the entire continent.
All of these scenarios are terrifying, even if they are all unlikely — for now. If any of them come to pass, it will take enormous restraint to prevent an asymmetric response. Even if the policy responses are the correct ones, one wrong move — a poorly communicated order, the wrong choice of target, simple human error, or an accident — could lead to a nuclear holocaust. The world has come closer to it more times than most people know, and only a fool would assume that luck will last forever.