Given the fragile global order in which we live, it is hard not to wonder whether the concept of "collective security" has been exhausted.
The answer depends on how we understand it. If by collective security we mean a system in which the world's leading powers renounce the use of force to change the status quo and pledge to act together against any state that violates that pledge, then it is not dead for one simple reason - it never really existed.
The classic version of collective security - most clearly embodied in the idea behind the League of Nations after World War I - seeks to overcome power politics by committing states to resolve their disputes peacefully and to unite against anyone who violates this principle.
Unfortunately, this concept assumes that aggressors will be easily recognized and that other states will have a unified opinion about who they are. It also requires that all major powers be prepared to act together against a powerful aggressor - an action that is costly, risky and often does not directly affect their own interests. In such situations, there will always be a temptation for some to stand aside and let others shoulder the burden.
Ultimately, this vision of collective security requires a level of trust and selflessness that in international politics is the exception rather than the rule.
However, there is also a more pragmatic understanding of collective security - as a set of arrangements aimed at making war less likely, or as military alliances in which a group of states unite to deter or defeat a common threat.
History knows many such examples. But even these more modest forms of collective security are not particularly effective - and over time they become even less so, making the future world more dangerous than the recent past.
Nevertheless, the relatively realistic models of collective security of the past deserve closer analysis today - if only to understand why they are barely surviving at present.
One limited form of such security is the so-called "security regime", in which rivals agree to limit their competition in clearly defined areas. Arms control agreements such as the SALT and START treaties are a good example.
They did contribute to a slight reduction in the risk of war, but they did not prevent the superpowers from accumulating thousands of nuclear warheads or from investing billions in increasing their destructive power. Even fewer succeeded in ending the deep-rooted rivalry between the Soviet Union and the West.
Today, the prospects for such agreements are even bleaker, in part because the world is no longer bipolar, as it was during the Cold War, but multipolar. This means that China must be included in any effective arms control framework. But there is currently no real effort to reach an agreement between Beijing, Moscow, and Washington, and China is reluctant to limit its arsenal until it catches up with the other two powers.
Instead, we are seeing an increase in nuclear arsenals, a modernization of military forces, and even discussions in a number of countries about acquiring nuclear weapons. Attempts to impose limits on artificial intelligence or cyberweapons have also failed—a completely unexpected result, given how difficult it would be to reach international agreement on such matters.
Another limited form of collective security is peacekeeping.
Once warring parties decide to end a conflict, neutral forces are deployed to monitor the agreement and instill confidence. But this mechanism only works if the parties truly desire peace. Peacekeepers usually do not have the power to stop a state or warlord from resuming hostilities. Peacekeeping is therefore a useful tool, but not a means of preventing war.
The most effective form of collective security—more accurately called "collective defense"—is military alliances.
Countries facing a common threat can increase their security through mutual defense and coordinated military training. Such alliances most often arise when there is a powerful state nearby, ready to use force to change the status quo. This is precisely what explains the creation of NATO, the US alliances in Asia during the Cold War, and the international coalition against Iraq in 1991.
This logic also manifested itself after the Russian invasion of Ukraine in 2022, when the US and much of Europe stood behind Kiev.
At the same time, it also explains the support that Russia received from China and North Korea. The case of Ukraine also shows something else - that collective defense does not always prevent war, because deterrence can fail.
During the Cold War, collective defense functioned relatively successfully, because both sides clearly realized that a military clash in Europe would lead to a catastrophic war between two powerful blocs.
Today, such predictability is lacking. There is no unified opinion on what the main threats are and how to respond. In Europe, perceptions of Russia diverge, the global South does not perceive it as an existential threat, and the US position seems unstable.
Furthermore, the conviction that Europe must take responsibility for its own security, while the US focuses on China, is increasingly being imposed in Washington. This leads to a divergence in strategic interests and inevitably weakens NATO, even if the alliance formally remains intact.
In Asia, the situation is equally precarious. Despite China’s growing power, efforts to create a stable counterweight are hampered by economic dependencies, regional rivalries, and the reluctance of individual states to shoulder the brunt. This increases the risk of miscalculations – including around Taiwan.
Finally, while alliances arise in response to threats, they are more resilient when they are also based on shared values. It is here that the West is experiencing its deepest crisis. Liberal democracy is in retreat, internal divisions are deepening, and the divergences between Europe and the United States – from Russia to the Middle East – are becoming increasingly apparent.
The conclusion is unpleasant but clear. The utopian version of collective security should not be relied upon.
States will continue to depend primarily on their own capabilities, even when seeking reliable partners. Strong alliances and defense capabilities do not preclude diplomacy, but they do not eliminate the risk of war.
Collective security may not be completely dead - but it is certainly not in good health.