Widespread Armed Conflicts Threaten Post-War Security Architecture
As the “Epic Fury” operation has been hitting Iran since February 28, 2026, the increase in armed conflicts signals the end of a certain concept of deterrence. From Ukraine to Gaza, from the Caucasus to the Middle East, something has gone awry in the security architecture that had prevented the return of conquest wars since 1945. Not a Third World War identical to the first two, but something potentially more insidious: a series of conflicts that no one seems able to contain anymore.
Since 1945 and the first use of nuclear explosives, a conviction has structured Western strategic thinking: the existence of these “absolute weapons” makes any war of conquest between major powers unthinkable, rendering the territory of nuclear-armed states inviolable. These nations could only confront each other indirectly, in limited wars, the intensity of which would never reach the hyperbolic violence of the first two world conflicts.
However, this certainty has been shaken. By invading Ukraine, a country whose independence and security it had guaranteed under the Budapest Memorandum in 1994, Russia used its nuclear arsenal as a shield (without risking direct involvement of the United States) to conduct a conventional war of conquest. This Russian invasion has caused a profound disruption of deterrence mechanisms, the consequences of which may not have been fully diagnosed.
A Shift in the Threshold
The scope of what is possible under the “nuclear umbrella” without triggering a collapse has increased significantly. The war in Ukraine demonstrated that a high-intensity conventional conflict, pursuing explicit territorial annexation objectives, could unfold without the activation of nuclear threats either by the aggressor to protect its gains or by states supporting Ukrainian defense to halt it.
The nuclear “threshold” concept, theorized in 1960, assumed a precise line beyond which nuclear war became certain. Since the war in Ukraine, this notion can no longer be strictly understood. In reality, behaviors adhere to more complex mechanisms: there is an area of uncertainty, an intermediate space where an infinite number of hostile acts remain possible without automatically leading to ultimate escalation.
In other words, we observe an elevation of the threshold beyond which the behavior of certain actors becomes intolerable. And it is precisely this elevation that opens a window of opportunity for “revisionist powers,” seeking to alter the rules of the system in their favor.
For example, by using force to annex new provinces, disregarding a cardinal principle of the United Nations: the inviolability of borders. According to this principle, borders cannot be altered by force, and any modification of their delineation can only occur within existing administrative boundaries. This principle had only seen rare exceptions in seventy years (Tibet acquired by China in 1950, Kashmir, the Korean demilitarized zone, Israeli-Arab wars, Northern Cyprus).
The Return of Conquest Wars
What we are witnessing is the most serious risk: not a Third World War intentionally declared by a power or group of powers, leading to total nuclear war, but a proliferation of simultaneous conventional conflicts exhausting American capabilities and will to respond, which could be considered a “world war under the threshold” (not initially involving the use of nuclear weapons).
Over the past five years, the most significant ruptures have been caused by nuclear-armed powers themselves. Russia attempted to subjugate Ukraine through a lightning offensive and formally annexed five provinces, before engaging in a protracted war with lasting consequences for European order. Israel, an undeclared nuclear power, responded to Hamas’ attack on October 7, 2023, with unprecedented military operations in Gaza, Lebanon, Syria, against the Houthis in Yemen, and finally, against Iran, following its doctrine of “disproportionate response.” Lastly, the United States, far from being mere spectators of the system’s deregulation, has become one of the actors: the operation in Iran was launched without UN mandate or consultation with Congress, and Washington openly threatens NATO members, undermining the institutions it had previously contributed to benefiting. The guarantor of the previous order, tired of funding the alliance, has initiated a brutal reform that disrupts its structure and threatens to destabilize it.
Other conflicts, without involving nuclear arsenals, have been launched not without correlation with these confrontations. In September 2020, Azerbaijan launched its first successful offensive on Armenia, gradually leading to the disappearance of the Republic of Artsakh and the exile of over 100,000 Armenians, without the international community being able to prevent this exodus. This conflict adds to the wars between Cambodia and Thailand, between India and Pakistan, or between Pakistan and Afghanistan. These situations highlight that the return of localized conflicts was not an accident but a significant trend, compounding the insurgency struggles of previous decades.
While not all these wars have resulted in significant border changes, neither the United States nor its strategic competitors can regulate all of these conflicts simultaneously. The United States could once balance all regions and tensions through external intervention (traditionally known as offshore balancing), but the multiplication of emergencies and conflicts no longer allows them, with an equal budget, to act effectively. The proliferation of conflicts shows that it has become much more challenging. This leaves much greater room for local actors to alter their relationships with neighbors.
Especially Russia has shown other revisionist powers that economic sanctions can be absorbed, that Western war efforts have industrial and political limits, and that nuclear protection provides a broader scope for conventional action than previously thought. All of this constitutes an “incentive,” in the precise sense given by game theory (an increase in reward for an action or a reduction of risk), to use force to reshape territories and power balances. To the extent of challenging the very nature of the international system?
When Conflicts Threaten to Merge
In his book “The Century of Total War,” published in 1951, Raymond Aron noted that American strategists in the immediate post-war period had only envisaged two scenarios: armed peace without direct confrontation or total war with a nuclear trigger. He believed they overlooked a third scenario, the “limited hot wars” like the Korean War in 1950 that caught America by surprise.
However, despite their sometimes terrible losses, none of these “hot wars” evolved into conflicts involving two coalitions directly intervening. External interventions, like those of the Soviet Union and China in favor of North Vietnam, had to be discreet, or restricted to defensive aid to protect the ally’s borders.
Nuclear deterrence had thus far confined local wars to the territories of the involved states. But the multiple, intense, scattered conflicts we are witnessing, unable to be stopped, have taken on such magnitude that a possibility has emerged: the creation of an integrated chain of conflicts (or more precisely concatenation), where all “local hot wars” produce a single uncontrollable conflict akin to the global wars of the 20th century.
To draw a metaphor from the field of electricity, during the Cold War (1947-1991) and the period of American power monopoly, conflicts worked in parallel on the international circuit. Each could flare up or extinguish independently of others without disrupting the system as a whole. A short circuit at one point did not affect the rest.
Our era may be reinstalling them in series: conflicts are now interconnected, so that each new flashpoint exacerbates previous ones and increases the burden on the entire circuit.
What Order to Prevent Escalation?
What would happen if a significant number of conflicts escalated in series? No power would be able to regulate local conflicts with sufficient projection of power.
Capable in theory of waging two major wars simultaneously, the US military can only practically conduct one at full intensity. The United States is experiencing one of the consequences of its global preeminence: it must be strong in all arenas at once, while each of its adversaries only needs to dominate its own region.
This structural asymmetry is at the heart of the risk of conflict escalation: a single additional crisis, over Taiwan, in the Gulf, or in the Indian subcontinent, would place Washington in a situation of strategic overload, unable to simultaneously contain all sources of tension.
Europe, still undecided on which direction to take, torn between transatlantic loyalty and strategic autonomy, is not united enough to replace the United States. China, despite its undeniable rise in power, lacks both the means (high seas fleet, a sufficient number of foreign bases) and the will to intervene in conflicts (its discretion in the Iran conflict shows a preference for resolving issues related to its hydrocarbon supply by others, at lower costs).
A world without a regulating power would be one where the deregulation of deterrence could potentially lead to the creation of a string of conflicts, possibly signaling a return to the hyperbolic violence of the first two world conflicts. Once triggered, this uncontrollable violence could endanger the security of nuclear-armed states themselves. Thus, we would be moving closer to conditions where weapons of mass destruction could be used, not at the beginning of a conflict as often thought but after establishing a state of sustained violence.
The end of the “indispensable nation” is inscribed in the rebalancing of GDPs of major powers. The international system is undoubtedly tilting towards a different model. However, this could take two very different forms: either it will be more distributed and polycentric, what political scientist Jean Baechler called the “oligopolar world,” or it will be a new bipolar system organized around Washington and Beijing. The question remains whether, in the intermediate period, the world will be spared a breakdown of deterrence and conflict management, which could lead to a new episode of uncontrollable violence similar to that of 1914-1945.
A passive security policy, based solely on the existence of nuclear arsenals and defensive alliances, is no longer enough to protect democracies. Therefore, by reaffirming themselves, they must contribute to building new regulatory mechanisms capable of keeping conflicts in parallel, preventing them from merging. This requires not only restoring shared norms on the use of force but also constructing a new security regime based on regional power balances capable of functioning without relying on an increasingly erratic sole guarantor.
