The Quiet Return of the Global Arms Race
Defence budgets are climbing at their fastest pace in decades. What's driving the spending — and where it could lead.
Military spending is rising worldwide at a pace not seen in a generation.
For a generation after the end of the last great ideological confrontation, the world grew accustomed to the idea that large-scale military competition belonged to the past. Defence budgets, as a share of national wealth, drifted downward across much of the world. The talk was of a peace dividend, of resources redirected from armies to schools and hospitals. That era is now clearly over. Around the world, military spending is climbing again, and it is doing so at the fastest pace in decades. A new arms race is under way — quieter and more diffuse than its Cold War predecessor, but no less consequential.
The scale of the shift is striking. States that spent years trimming their armed forces are now expanding them, replacing aging equipment, and investing heavily in new capabilities. The change is not confined to any one region; it is global, encompassing established powers and rising ones, wealthy nations and poorer ones. The cumulative effect is a world that is arming itself more rapidly and more broadly than at any time in recent memory. Understanding why — and where it leads — is essential to understanding the trajectory of world affairs.
The security dilemma returns
At the heart of every arms race lies a mechanism that political scientists call the security dilemma. It works like this: a state, feeling insecure, builds up its military to defend itself. But its neighbours and rivals, unable to see into its intentions, interpret the buildup as a threat and respond by arming themselves. The first state, seeing the response, feels more insecure still, and builds up further. Each side acts defensively, yet the result is a spiral of mounting armament that leaves everyone less secure than before.
This dynamic, dormant for years, has reawakened. As rivalries sharpen and trust erodes, states increasingly look to military strength as the ultimate guarantee of their security, discounting the diplomatic and institutional arrangements that once offered reassurance. Each buildup triggers responses, and the responses trigger further buildups. The tragedy of the security dilemma is that it can drive an arms race even when no one actually wants war — a machine that, once started, is very hard to stop.
The tragedy of an arms race is that each side arms in self-defence, and the sum of all that defence is a world less safe.
What is different this time
Today's arms race differs from earlier ones in important ways. It is not a simple two-sided contest between rival blocs, but a multipolar scramble involving many powers with overlapping and shifting rivalries. This makes it harder to manage: the bilateral arms-control frameworks that helped stabilise earlier competitions do not fit a world of many competing actors. An agreement between two powers means little if a third is unconstrained.
The technology is different too. Much of the current spending is directed not at traditional platforms but at new domains and capabilities — uncrewed systems, precision munitions produced at scale, space-based assets, and the software that ties them together. These technologies are often cheaper, more widely available, and harder to count and verify than the tanks and warheads of the past. That makes the new arms race both more accessible to smaller powers and more difficult to constrain through the old methods of inspection and limitation.
The economics of rearmament
Rearmament is expensive, and the money has to come from somewhere. Sustained increases in military spending compete with everything else a government might fund — infrastructure, health, education, debt reduction. In the short term, defence spending can stimulate industry and employment, particularly where it supports a domestic arms sector. But over the long term, resources devoted to weapons are resources not available for the investments that build lasting prosperity. The peace dividend of the past is being spent down, and a rearmament bill is taking its place.
There is also a political economy to arms races that gives them momentum. Defence industries, once expanded, develop powerful interests in continued spending. Supply chains, jobs and regional economies come to depend on military procurement. This creates constituencies that lobby for sustained or increased budgets regardless of the strategic situation, making it politically difficult to reverse course even when tensions ease. Arms races, once entrenched, tend to sustain themselves.
The erosion of arms control
What makes the current buildup especially worrying is that it is occurring as the frameworks meant to restrain it are crumbling. The treaties and agreements that once capped arsenals, mandated transparency and provided for verification have lapsed, been abandoned, or failed to keep pace with new technologies. The result is a buildup with fewer guardrails than at any point in recent decades — more weapons, less transparency about them, and weaker mechanisms for managing the competition.
Arms control was never about disarmament for its own sake. Its real value was in reducing uncertainty and the risk of miscalculation. Transparency about capabilities reassured rivals about intentions; limits provided predictability; verification built the modest trust needed to sustain further agreements. As these mechanisms erode, that reassurance disappears, and the security dilemma operates with fewer checks. A buildup in the dark is far more dangerous than a buildup in the open.
Where it could lead
Arms races do not always end in war. Some are eventually stabilised by negotiation, others by the exhaustion of one side, still others simply fade as tensions ease. But history offers a sobering lesson: heavily armed rivals, locked in mutual suspicion and stripped of the mechanisms to communicate and reassure, are more likely to stumble into conflict, whether through miscalculation, accident or the momentum of crisis. The weapons themselves do not cause wars, but they shorten the distance between a crisis and a catastrophe.
Weapons do not start wars, but they shorten the distance between a crisis and a catastrophe.
The quiet return of the global arms race is thus more than a story about budgets and hardware. It is a symptom of a deeper condition: a world in which states increasingly doubt that anything other than force can guarantee their security, and in which the tools for managing that fear have fallen into disrepair. Reversing the trend would require rebuilding trust, reviving arms control adapted to new technologies, and restoring the belief that security can be found through arrangement as well as armament. That is a tall order in the current climate. But the alternative — an unconstrained, multipolar arms race running on the logic of fear — is a prospect sobering enough to make the effort worthwhile.