The post-1945 global security architecture, commonly described as a “rules-based order,” is facing its greatest test since World War II. As great powers give up on diplomacy, middle powers are seeking viable alternatives, raising the question: what could this lead to?
The rules-based order emphasised the development and stewardship of international law, alongside the establishment of institutions such as the United Nations and its affiliated bodies. Its core objective was to institutionalise international accountability and prevent the recurrence of atrocities on the scale witnessed during World War II and earlier conflicts.
To reinforce this system, a network of international financial institutions, most notably the World Bank and the International Monetary Fund, was created to support economic development in lower-income states. By facilitating access to capital and promoting economic stability, these institutions aimed to address structural conditions that could lead to conflict.
Within this order, international law was shaped around key principles: the right to self-determination, respect for state sovereignty, non-intervention, and operation within the legal and institutional framework of the United Nations system.
From an analytical standpoint, the UN and the broader rules-based order have rarely been effective in preventing conflicts outright. However, they have provided a framework for attributing responsibility and, in some cases, holding individuals accountable for initiating wars or committing atrocities.
This tension persisted into the post-9/11 era. During the “war on terror,” the United States intervened in Afghanistan and Iraq, assembling multinational coalitions partly to mitigate international backlash, yet without explicit authorisation from the UN Security Council. At the same time, however, the P5+1 (Russia, China, the United States, France, and the United Kingdom plus Germany) successfully negotiated a landmark agreement with Iran over its nuclear program after more than a decade of diplomacy [1]. Endorsed by the United Nations and supported by the International Atomic Energy Agency, the deal exemplified the aspirational function of the rules-based order: fostering accountability, multilateralism, and coordinated international action.
The most significant shocks to this order began in 2014, when Russia annexed Crimea from Ukraine [2]. This episode was particularly consequential because international orders are most vulnerable when their principal architects and guarantors, especially the permanent members of the UN Security Council (the P5), disregard them. In such instances, the erosion of norms becomes systemic rather than marginal. In the case of Crimea, Russia’s actions were widely viewed as a violation of foundational principles of international law, including territorial integrity and the prohibition on the use of force under the UN Charter.
More broadly, the crisis illustrated how the rules-based order fractures when core norms, such as the peaceful resolution of disputes, are ignored by major powers. The limited and largely indirect response by the international community, primarily through sanctions, exposed the system’s constraints and arguably emboldened further violations. Russia’s subsequent full-scale invasion of Ukraine less than a decade later reinforced the perception that breaches of the system can occur with insufficient deterrence [3].
Beyond interstate conflict, international legal norms surrounding genocide and ethnic cleansing have also been repeatedly tested. Despite emerging in response to the Holocaust, these norms failed to prevent atrocities such as the Iraqi genocidal ‘Anfal’ campaign in Kurdistan during the late 1980s [4]. More recently, Israel’s military operations in the Gaza Strip have been described by some observers as constituting forms of genocide or ethnic cleansing, underscoring the contested and uneven application of international humanitarian law [5].
Of particular significance is the extent to which the rules-based order has also been undermined by its principal architect, the United States. Recent policy trajectories have been interpreted by some analysts as sidelining the United Nations and weakening multilateral frameworks [6,7]. This includes debates over potential territorial ambitions, such as renewed proposals to acquire Greenland, sometimes framed in strategic or security terms, as well as positions that appear to tolerate or normalise territorial changes achieved by force, including Russia’s occupation of parts of Ukraine [8-11]. Additional controversial measures include actions targeting Venezuela’s leadership and the imposition of sanctions on members of institutions such as the UN Human Rights Council and the International Criminal Court. The World Health Organization, and even NATO, are often criticised as weak or overly reliant on US funding, particularly when their positions diverge from US policy [12,13].
Taken together, these developments point to a broader pattern: the gradual erosion of the rules-based order not only by revisionist powers but also by those instrumental in its creation, raising fundamental questions about its durability and future relevance.
What Comes Next?
For the major powers, the evolving posture of the United States is unlikely to go unanswered. One plausible trajectory is a shift toward a Cold War-style multipolar arms race involving several nuclear-armed states rather than a bipolar standoff. The prospective expiration, or erosion, of key arms control frameworks such as the New Strategic Arms Reduction Treaty, combined with explicit US ambitions to expand military capabilities, including advanced missile defence initiatives like a proposed “golden dome,” reinforces this risk trajectory [14].
Such dynamics are unlikely to remain confined to great-power competition. They may cascade into already fragile regions, particularly the Middle East, where threat perceptions have historically driven rapid military expansion. Gulf Cooperation Council states are investing in drone interception systems, surface-to-air missiles, and enhanced offensive capabilities. Meanwhile, Turkey is advancing an ambitious domestic defence industrial program, and Egypt is accelerating the development of indigenous drone technologies and air defence systems. Of particular note is speculation around a potential strategic alignment, sometimes described as a “New Sunni Axis”, involving Egypt, Pakistan, Turkey, and Saudi Arabia [15]. While still hypothetical, such a configuration would signal a significant reordering of regional security dynamics.
Beyond arms racing, the gradual displacement of a rules-based order by a more explicitly power-driven system carries deeper structural risks. In such an environment, international law and institutions may become increasingly ineffective as constraints on state behaviour. This erosion reduces both deterrence against aggression and the availability of credible mechanisms for conflict resolution, increasing both the likelihood and duration of interstate conflicts.
Historically, power-based systems have been associated with high-intensity rivalry and systemic wars. A reversion to such a model – particularly under contemporary conditions of advanced military technologies, including precision-strike capabilities, cyber warfare, and nuclear modernisation – would significantly elevate the stakes. The cumulative effect is a more volatile and less predictable international system, with potentially severe and enduring global consequences.
Is the Rules-Based Order Salvageable?
Recent developments have sparked a global debate, particularly among middle powers, which are often most sensitive to the erosion of the rules-based order. At its core lies a fundamental question: will states continue to see sufficient value in restraint, collective action, and institutional legitimacy to sustain the system?
In response to growing uncertainty, many middle powers are diversifying partnerships and recalibrating their strategic positioning to navigate an increasingly volatile environment. A prevailing view is that the rules-based order is unlikely to disappear outright but will instead evolve, potentially strengthened through reform and reinforcement of its legal and institutional foundations rather than abandoned.
Structural realities reinforce this perspective. No single state possesses the capacity to unilaterally dominate the international system sustainably, just as no state can operate in isolation without incurring significant economic, political, and security costs. Interdependence remains a defining feature of the contemporary global order, making cooperation not optional but necessary.
At the same time, the durability of any order depends on how responsibilities are distributed. When these burdens fall disproportionately on a single global power, that state may accrue outsized influence while others become increasingly dependent and strategically vulnerable. A more balanced distribution of commitments, anchored in genuine political will, would enhance both the legitimacy and resilience of the system over time.
References:
- European External Action Service, “Nuclear Agreement – JCPOA,” EEAS, accessed April 13, 2026, https://www.eeas.europa.eu/eeas/nuclear-agreement-%E2%80%93-jcpoa_en.
- BBC News, “Ukraine Crisis in Maps,” accessed April 13, 2026, https://www.bbc.com/news/world-europe-26644082.
- CNN, “Ukraine,” accessed April 13, 2026, https://edition.cnn.com/world/europe/ukraine.
- Human Rights Watch, “Genocide in Iraq: The Anfal Campaign Against the Kurds,” 1993, https://www.hrw.org/reports/1993/iraqanfal/ANFALINT.htm.
- Human Rights Watch, “Israel’s Crime of Extermination, Acts of Genocide in Gaza,” December 19, 2024, https://www.hrw.org/news/2024/12/19/israels-crime-extermination-acts-genocide-gaza.
- “UN Experts Call for Immediate Dismantling of Gaza Humanitarian Foundation,” Office of the United Nations High Commissioner for Human Rights, August 2025, https://www.ohchr.org/en/press-releases/2025/08/un-experts-call-immediate-dismantling-gaza-humanitarian-foundation.
- “Charter,” Board of Peace, accessed April 13, 2026, https://boardofpeace.org/charter.
- Matthew Olay, “Trump Announces U.S. Military’s Capture of Maduro,” S. Department of Defense, January 3, 2026, https://www.war.gov/News/News-Stories/Article/Article/4370431/trump-announces-us-militarys-capture-of-maduro/.
- CNN Politics, “Trump Won’t Rule Out Military Force to Take Greenland,” January 21, 2026, https://edition.cnn.com/2026/01/21/politics/military-force-us-greenland-trump.
- “President Donald Trump Meets with Russian President Vladimir Putin at Joint Base Elmendorf Richardson in Anchorage, Alaska,” The White House, August 15, 2025, https://www.whitehouse.gov/gallery/president-donald-trump-meets-with-russian-president-vladimir-putin-at-joint-base-elmendorf-richardson-in-anchorage-alaska/.
- Chantelle Lee, “Trump Again Hints at Desire to Annex Canada, Calling Carney ‘Future Governor,’” TIME, March 10, 2026, https://time.com/article/2026/03/10/trump-carney-canada-future-governor-annexation/.
- “Imposing Sanctions on the International Criminal Court,” The White House, February 6, 2025, https://www.whitehouse.gov/presidential-actions/2025/02/imposing-sanctions-on-the-international-criminal-court/.
- “US Sanctions on Special Rapporteur Francesca Albanese Threaten Human Rights System: UN Experts,” Office of the United Nations High Commissioner for Human Rights, August 8, 2025, https://www.ohchr.org/en/statements/2025/08/us-sanctions-special-rapporteur-francesca-albanese-threaten-human-rights-system.
- Chad de Guzman, “China, North Korea, and Russia’s Response to Trump’s ‘Golden Dome’ Proposal,” TIME, May 27, 2025, https://time.com/7288728/golden-dome-trump-north-korea-russia-china-response-space-militarization/.
- “Netanyahu Says Israel Will Forge Regional Alliance to Rival ‘Radical Axes,’” Al Jazeera, February 22, 2026, https://www.aljazeera.com/news/2026/2/22/netanyahu-says-israel-will-forge-regional-alliance-to-rival-radical-axis.
The views expressed in this publication are those of the author and do not necessarily represent the views of MERI.