June 26, 2025 marked 80 years since the signing of the United Nations (UN) Charter – a founding international pledge to resolve conflicts through dialogue and prevent future wars. Since then, the UN has led peacekeeping and peacebuilding efforts in some of the world’s most fragile regions. Yet in recent years, this pledge has come under increasing strain. Once in decline, conflicts between sovereign states have recently risen, and concerns over the global commitment to multilateralism have deepened.
In response, there have been increasing calls for the UN to re-centre on its foundational mandate of fostering international peace. The 2024 Multilateralism Index (produced by IEP and the International Peace Institute) shows that while formal UN engagement remains steady and has even expanded in some areas, actual outcomes have deteriorated, with peace and security showing the steepest declines in multilateral performance over the past ten years. While the UN’s procedural mechanisms persist, their effectiveness is increasingly constrained by a loss of institutional momentum in today’s fragmented and militarised global landscape.
As we detail in the 2025 Global Peace Index (GPI), the world is experiencing its highest level of conflict since World War II, with 59 active state-based conflicts and 152,000 deaths in 2024. The economic impact of violence is now US$19.97 trillion, or 11.6 per cent of global GDP, driven by rising military spending and conflict-related losses. This marks a 3.8 per cent increase from 2023 and a 12.5 per cent rise since 2008.
Military and internal security costs alone totalled nearly $15 trillion in the past year, while peacekeeping and peacebuilding received just $47 billion, only 0.5 per cent of military spending and 0.3 per cent of total violence-related costs, as shown in the following figure.
Between 2008 to 2024, peacekeeping and peacebuilding funding declined by 26 per cent, with peacebuilding falling 39 per cent (from $8.7 billion to $5.3 billion) and peacekeeping down to $5.8 billion. The only major increase came in 2022, when spending briefly spiked to $10 billion following the Russian invasion of Ukraine, before dropping again. These trends highlight a reactive approach: short bursts of funding during crises, followed by cutbacks, rather than sustained investment.
Despite a nearly unchanged number of missions over the past two decades (60 in 2008 vs 61 in 2024), the number of deployed peacekeeping personnel has halved – from 187,586 to 94,451 – largely due to funding shortfalls.
Peacekeeping has become a cornerstone of modern conflict management, evolving from Cold War-era inter-state missions to complex operations in civil conflicts. Despite funding shortfalls and rising global tensions, it remains vital for sustaining peace. This makes it essential to understand the conditions that drive mission success. Nearly 80 years of experience point to several key factors behind effective operations.
Peacekeeping success relies on legitimacy and consent. Missions must be seen as credible by local communities and accepted by the conflicting parties. This legitimacy comes from proper authorisation, respect for international law, and local trust.
Such dynamics were largely at play in the work of the United Nations Transition Assistance Group (UNTAG) in Namibia (1989-1990). This mission shows how clear legitimacy, strong mission design, and genuine local ownership can enable peacekeeping to effectively support a country’s transition to independence. Overseeing Namibia’s transition to independence from South Africa in the context of a decades-long insurgency, UNTAG oversaw a ceasefire, monitored the withdrawal of South African forces, ensured the repatriation of refugees, and administered free and fair elections. It included over 7,500 personnel at its peak, a mix of civilian, police and military. UNTAG is widely regarded as a success for establishing the foundation of a stable, democratic Namibia and the first instance of international constitution-making assistance.
Peacekeeping success depends on well-designed missions. Adequate personnel, context-appropriate mandates, sufficient resources, clear operational guidance and tailored structures are key. In complex conflicts, realistic goals and trained staff boost credibility, long-term impact and ability to adapt to changing conditions, while the quality and number of personnel affect the capacity to resolve post-conflict tensions. Research also highlights that tailored structures and defined roles enhance credibility and outcomes.
The conclusion of the Mozambican Civil War (1977-1992) offers a strong example of how a well-structured mission can deliver results. Following the 1992 Rome General Peace Accords, which ended a protracted civil war between the government (FRELIMO) and rebel group (RENAMO), the UN deployed the United Nations Operation in Mozambique (ONUMOZ). The mission focused on enforcing the ceasefire, overseeing the demobilisation of troops, and supporting post-conflict elections. Backed by a robust police presence of over 1,000 civilian police observers, ONUMOZ operated with clear goals and exited promptly after successful elections and the announcement of results.
The context in which peacekeepers operate is critical to success. Smaller missions can work in stable settings, but struggle in divided societies. Local ownership, political will and economic conditions are crucial for lasting impact. Peacekeeping only endures when grounded in local realities and tied to long-term peacebuilding.
Cambodia illustrates both the promise and limits of international intervention. Following decades of violence under the Khmer Rouge and a protracted civil war, the 1991 Paris Peace Accords marked the beginning of a peace process. The United Nations Transitional Authority in Cambodia (UNTAC) was deployed to implement the agreement, with over 20,000 personnel. The mission disarmed factions, repatriated refugees, facilitated democratic elections and restored civil governance. However, despite these early achievements, UNTAC’s long-term impact was constrained by weak local ownership and persistent political instability, highlighting the importance of sustained local engagement beyond initial peacekeeping efforts.
As geopolitical tensions escalate and multilateral cooperation frays, peacekeeping and peacebuilding demand renewed UN focus. Limited resources make it critical to study what works, drawing lessons from many successful missions to guide the role the UN can play.
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Identifying and measuring the factors that drive peace
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