As Russian tanks rolled into Ukraine in 2022, one threat loomed over all battle plans – the spectre of mushroom clouds. Vladimir Putin’s sabre-rattling about his nuclear arsenal cast a long shadow on the conflict, silently warning NATO to keep its distance. Now, leaders from Beijing to Pyongyang are surely taking note. If brandishing nukes can hold powerful enemies at bay, what does that mean for the next crisis? From Eastern Europe to East Asia and the Middle East, the Ukraine war may be rewriting the playbook for would-be aggressors.

Russia’s Nuclear Shield in the Ukraine War

When Russia launched its full-scale invasion of Ukraine, it wasn’t just troops and tanks in play – it was the implicit threat of nuclear force. Early on, President Putin pointedly put Russia’s nuclear forces on alert and reminded the world of Russia’s ultimate weapons. He “repeatedly raised the spectre” of using a nuclear weapon if NATO intervened too directly, hinting Moscow might resort to its “ultimate arsenal” should Western militaries jump in[2]. This thinly veiled nuclear warning had an immediate effect: NATO and the United States ruled out sending troops or enforcing a no-fly zone over Ukraine, wary of any step that could spark a direct superpower clash. Western officials openly acknowledged the need to avoid World War III, calibrating support to Ukraine in ways that would help Kyiv but not cross the Kremlin’s nuclear red lines.

From Washington’s perspective, this extreme caution was about preventing escalation. American and European leaders confined their aid to weapons, intelligence, and economic sanctions – stopping short of any intervention that would put NATO forces into direct combat with Russians. In effect, Russia’s nuclear arsenal worked like a protective shield over its aggression. Analysts note that Putin’s nuclear sabre-rattling has been dangerously effective in scaring off outside intervention, to the point that one expert called Russia’s nuclear blackmail “a spectacular success” for deterring the West[3]. Indeed, the U.S. and its allies flatly rejected risky proposals (like enforcing a Ukraine no-fly zone or breaking Russia’s Black Sea blockade) specifically because those could trigger direct war with a nuclear-armed Russia[4].

This dynamic illustrates how nuclear weapons shaped the Ukraine war. Knowing Russia’s massive arsenal lurked in the background, NATO opted for restraint. Western military aid has been extensive, but always delivered at arm’s length – no Western soldiers officially fight on Ukrainian soil. The Kremlin, for its part, continually reminds the world of its nuclear capabilities (whether by state TV pundits musing about Armageddon or by moving nuclear-capable missiles to Belarus). All of this has kept other nations from intervening militarily on Ukraine’s behalf. The result is a brutal conventional war being fought within limits – horrifically destructive to Ukraine, but never expanding beyond its borders. In Moscow’s eyes, its nuclear threats likely “scared off Western intervention” and kept NATO at bay[5]. In Washington’s eyes, the shadow of Mutually Assured Destruction (MAD) imposed caution on all sides: no one wants to gamble with a nuclear apocalypse[6]. However one interprets it, the Ukraine war has underscored a grim lesson: a nuclear-armed aggressor can wage war with a degree of impunity, because other powers fear provoking a wider nuclear catastrophe.

China’s Taiwan Calculus: Lessons from Ukraine

It’s not lost on Beijing that Russia’s nuclear sabre-rattling constrained the West in Ukraine. Chinese strategists have been watching the conflict closely, parsing what it means for their own ambitions – especially the decades-old goal of “reunifying” Taiwan. A key takeaway for China’s leaders may be that nuclear deterrence by an aggressor enables aggression. As one analysis put it, “nuclear deterrence by the aggressor (Russia in Ukraine, China in Taiwan) enables conventional war and blunts outside intervention.” In other words, if you have nukes and threaten to use them, other major powers might stand down[7]. The Ukraine war could thus reinforce Beijing’s belief that its own nuclear arsenal is a crucial trump card for keeping the U.S. and allies from directly defending Taiwan[8].

China has historically maintained a relatively modest nuclear stockpile compared to Russia or the U.S., but this appears to be changing fast. Recent data shows that China is rapidly expanding its arsenal – from roughly 235 warheads in the early 2000s to about 410 by 2023 – overtaking long-established nuclear powers like Britain and France[9]. U.S. intelligence reports and Pentagon assessments warn that China could field 700+ warheads within a few years and 1,000+ by 2030. Beijing is literally building hundreds of new missile silos in its western deserts. This buildup suggests China wants a more formidable nuclear deterrent, one that could make Washington think twice in a crisis. European analysts note with alarm that “China’s massive expansion of its nuclear arsenal” runs counter to arms-control hopes[10]. But from China’s viewpoint, more nukes mean more security – and more leverage.

If a conflict erupts over Taiwan, China would likely wield nuclear threats to deter any U.S.-led military response. Chinese officials have already declared that they would not hesitate to “declare a state of war” if certain red lines (like formal Taiwanese independence or U.S. troops stationed on Taiwan) were crossed[11]. It’s widely assumed that, much as Putin did with Ukraine, Beijing would warn off the United States, Japan, and others by brandishing the threat of nuclear escalation. The goal would be to induce “self-deterrence” in Western capitals – basically scare the US into staying out. And judging by Ukraine, Chinese leaders might have reason to think it could work. As the Atlantic Council observed, “China could very well conclude that inducing self-deterrence in Western capitals has worked well in Ukraine, and is a promising approach for Taiwan”[12].

Of course, there are big differences between Ukraine and Taiwan. The U.S. has no defense treaty with Ukraine, but it does have longstanding (if ambiguous) commitments to help Taiwan. American forces regularly train and equip Taiwan’s military, and top U.S. officials have hinted the U.S. would intervene in a Taiwan invasion. This could make an Asia-Pacific crisis far more prone to escalation. Yet the underlying logic remains: China’s nuclear weapons greatly raise the stakes. The prospect of nuclear war might restrain the U.S. just as it did in Ukraine – or at least make Washington much more cautious in how it fights. In any case, Beijing’s nuclear expansion sends a message. As one European security report bluntly concluded: Russia’s nuclear blackmail to keep the West out of Ukraine, and China’s rush to build more nukes, are forcing the world to accept that nuclear deterrence is here to stay – and perhaps spreading[13].

North Korea: Nuclear Bluster and Regime Survival

No country is more unapologetic about nuclear blackmail than North Korea. For Pyongyang’s Kim Jong Un, the Ukraine war simply validates what he already believed – nuclear weapons are his ultimate insurance policy. North Korean state media have pointedly contrasted Ukraine’s fate with North Korea’s own situation: Ukraine surrendered its Soviet-era nukes in the 1990s and later got invaded; North Korea built nukes and claims it will never suffer the same fate. In fact, Pyongyang openly flaunts its willingness to use nuclear force to deter or defeat enemies. In 2022, the North Korean regime even codified a new law allowing preemptive nuclear strikes “to protect itself” and even “gain the upper hand during a war,” explicitly spelling out scenarios where it might launch first[14]. This goes far beyond the traditional notion of nukes as last-resort defensive weapons. For Kim, they are a tool of coercion – a way to keep the U.S., South Korea, and Japan in check by fear.

Kim Jong Un has repeatedly test-launched intercontinental ballistic missiles and issued blood-curdling threats of nuclear attacks on U.S. and allied targets. Why? Because he’s confident that even a small nuclear arsenal can make bigger powers blink. North Korea may have only a few dozen warheads (versus hundreds or thousands held by the superpowers), but even a chance that Pyongyang could nuke Seoul, Tokyo, or Los Angeles gives the world pause. As one assessment noted, Kim hopes that his handful of nukes is “enough to make America think twice (it probably is – no U.S. [president would risk losing a U.S. city])”[15]. In essence, North Korea has created a mini version of Mutually Assured Destruction with the United States: Washington knows attacking Kim’s regime could provoke nuclear retaliation on U.S. allies (or even the U.S. homeland), while Kim knows actually using his nukes would invite all-out U.S. retaliation that would annihilate his regime[16]. This unstable equilibrium has so far kept the peace – despite fiery rhetoric, Pyongyang hasn’t dared actually use a nuclear bomb, and the U.S. hasn’t dared to attack North Korea outright. Deterrence, however fragile, is doing its grim job.

From North Korea’s perspective, the Ukraine war is a cautionary tale: if you don’t have nukes, you risk invasion; if you do have nukes, you can get away with astonishing belligerence. It’s no coincidence that Kim Jong Un declared North Korea’s nuclear-armed status “irreversible”. His regime will never entertain disarmament – on the contrary, it continues to test more advanced missiles (including solid-fuel ICBMs and submarine-launched missiles) and likely build more warheads. The message to the world is explicit: North Korea sees nuclear weapons as a guarantee of regime survival and a license for aggression. Kim is effectively telling others: “Don’t interfere with me, or you might get nuked.” And so far, the international response – mostly sanctions and stern statements – has not imposed any real cost on Pyongyang’s nuclear bravado[17]. It’s nuclear blackmail in pure form, and every passing year that it goes unpunished is a lesson to other would-be nuclear states.

Iran’s Nuclear Ambitions: Eye on Israel and the U.S.

For Iran, which doesn’t yet have nuclear weapons, the Ukraine war’s lesson is being absorbed with keen interest. Iranian leaders publicly insist they aren’t seeking the bomb – citing religious edicts against weapons of mass destruction – but their actions (like enriching uranium to near weapons-grade) tell a more ambiguous story. Geopolitically, Iran can’t ignore what’s happening: they see that North Korea, once it got nukes, can even deter superpowers, while states that gave up nuclear programs – like Libya (which disarmed in 2003) or Ukraine – later became vulnerable to regime overthrow or invasion[21]. This object lesson isn’t lost on hardliners in Tehran. As analysts from The DEFCON Warning System have observed, “some Iranian strategists likely see deterrence value in nukes”[22]. If Iran had even a few nuclear warheads, it could dramatically shift the power balance in the Middle East. Suddenly, Tehran might calculate that the United States would hesitate to intervene militarily against an Iranian aggression for fear of sparking a nuclear exchange.

One hypothetical scenario often discussed is an Iranian showdown with Israel. Iran’s clerical regime frequently calls for the end of the Israeli state (though mostly in rhetorical terms), and Israel for its part views a nuclear-armed Iran as an existential threat. Currently, Israel is widely believed to have its own undeclared nuclear arsenal, serving as the ultimate safeguard against annihilation. If Iran were to build the bomb, the region would enter a true MAD standoff between Tehran and Tel Aviv[23]. In theory, mutual nuclear fear could make both sides more cautious – much as India and Pakistan, or the US and USSR, avoided outright war once both had nukes. But the Middle East’s brew of ideological zeal, proxy militias, and hair-trigger hostilities would make a nuclear balance particularly perilous. Miscalculations or extremist gambits could spiral out of control. Iranian leaders might believe that having nukes would deter the US from coming to Israel’s aid in a conflict (just as Russia’s nukes deterred aid to Ukraine). And indeed, if Tehran could threaten American cities – or U.S. forces in the Gulf – Washington might have to think twice about marching to Israel’s rescue. On the flip side, Israel might feel compelled to take pre-emptive action before Iran ever reaches that point, precisely to avoid being held hostage by Iranian nuclear blackmail down the road.

At present, Iran remains a threshold nuclear state – capable of producing a bomb’s worth of fissile material in fairly short order, according to the UN, but not confirmed to have built an actual weapon. The Ukraine war seems to underline the benefits of crossing that threshold. It shows Tehran’s hardliners a compelling cause-and-effect: get the bomb, and you can pursue aggression (via proxies or directly) with a protective nuclear umbrella that keeps America and others at bay. In the Iranian view, nuclear weapons could be the key to freely projecting power in the region without inviting direct U.S. military retaliation. This is sobering for Israel, the U.S., and Gulf Arab states – all of whom fear that an Iranian bomb would embolden Tehran’s adventurism. Some Israeli officials point to Iran’s consistent pattern of avoiding direct wars (preferring proxies like Hezbollah) as evidence that Iran’s leaders are rational and deterrable. If Iran did obtain nukes, optimists hope it would use them defensively (to assure regime survival) rather than offensively. Still, the mere introduction of another nuclear-armed state in such a volatile region would raise the risk of a catastrophic miscalculation. The threat of nuclear blackmail would hang over every crisis – a grim new factor for diplomats and generals to consider.

The New Era of Nuclear Blackmail?

The chilling takeaway from all these cases is that nuclear weapons are making a comeback as enablers of aggression. In the post-Cold War decades, many believed (or hoped) that nuclear sabre-rattling was a thing of the past – a last-resort deterrent, not a usable tool of statecraft. The war in Ukraine has shattered that illusion. It demonstrated in real time that a nuclear-armed power can invade its neighbour and effectively intimidate the rest of the world into limiting its response. This precedent has not gone unnoticed. We are likely entering an era where more states may calculate that nuclear weapons open doors: doors to territorial expansion, regime preservation, or regional dominance, all achieved under the nuclear shadow.

Consider the ripple effects so far:

• Arms Buildups: Far from shrinking, nuclear stockpiles are growing in several countries. China is the most striking example of rapid expansion[24], but Pakistan, India, and North Korea have also been adding warheads. Even Russia and the U.S., while not racing in numbers, are modernising their arsenals with new missiles and warheads. The overall trend is toward more nuclear arms in more hands[25], reversing decades of arms control progress.
• New Nuclear Aspirants: The success of Russia’s nuclear coercion could embolden countries on the fence about pursuing nukes. Already, strategists in places like Iran and perhaps Saudi Arabia are surely thinking that not having the bomb is a major strategic handicap[27]. The old security guarantees – like NATO’s umbrella or UN assurances – look less convincing after Ukraine. In Asia, U.S. allies like South Korea and Japan have also had public debates about whether they need their own nuclear deterrent if the U.S. might hesitate to act under nuclear duress.
• Bolder Brinkmanship: Nuclear rhetoric is becoming more commonplace. Russian officials now routinely make veiled (or explicit) nuclear threats on state TV. North Korea publishes videos simulating nuclear strikes. The taboo against talking about using nukes has eroded, and with it comes the worry that the threshold for using a “tactical” nuclear weapon might lower. Each time Putin’s bluster goes unpunished, or Kim’s threats draw concessions, the concept of nuclear blackmail is reinforced as a viable strategy. That could make future showdowns – a Taiwan Strait crisis, an India-Pakistan clash, an Israel-Iran confrontation – even more unpredictable and dangerous.

Yet, despite these dark trends, it’s worth noting that direct nuclear conflict has so far been avoided. In Ukraine, NATO’s caution and Russia’s restraint (however cynical) have meant that the worst-case scenario – nuclear bombs actually being used – has been averted. The fear of mutually assured destruction still holds a powerful sway over decision-makers[29]. Even Kim Jong Un, for all his threats, hasn’t dared cross the line into actual nuclear use, likely because he knows it would be national suicide[31]. So while nuclear blackmail is transforming how wars are waged and how other nations respond, the underlying logic of deterrence is not dead. It’s just become more complex.

For the general public, all this can be unsettling. We’re entering a world where major wars might be “contained” by nuclear threats – until they’re not. The Ukraine war may prove to be a template: a nuclear-armed aggressor attacking a non-nuclear neighbour, Western powers constrained to indirect support, and the conflict grinding on destructively. If so, we could see more “Ukraine scenarios” in the future. A Chinese move on Taiwan, an Indian-Pakistani border war, or a Middle East eruption could play out under similar shadow of nuclear caution. Each situation will have its own nuances, but the basic equation – nukes = caution for outside parties – seems here to stay.

In the end, the threat of nuclear weapons is a double-edged sword. On one hand, it may deter total war between great powers (nobody wants to trade blows directly with a nuclear-armed foe). On the other hand, that very hesitation can embolden those same nuclear-armed powers to act aggressively below the nuclear threshold, assuming others will shy away. It’s a perilous tightrope. The world will need deft diplomacy, stronger international norms, and perhaps new arms control efforts to prevent nuclear posturing from spiraling into actual catastrophe. The lesson from Ukraine is stark: nuclear blackmail works – but only until someone decides to call the bluff. In future wars, we can expect the threat of the bomb to loom large. Whether humanity can keep that threat from becoming reality will be the ultimate test of our collective wisdom.