Later this year, UN member states will choose the tenth Secretary-General of the United Nations. In today’s fractured and volatile world, we need a Secretary-General who will fulfill the mandate with conviction and significant political courage.

The UN Charter does not envision the Secretary-General as a passive administrator. It calls for a leader who is both a diplomat and an advocate. Fulfilling that mandate requires the fortitude of someone who will not necessarily act as a Secretary, but a General – someone who can marshal a large, risk averse bureaucracy to be fit for purpose and respond to the needs of the hour. The next Secretary-General must restore the UN’s geopolitical relevance, lead decisively on peace and security and project a strong global presence. They must bring vision and authority to the role and the ability to coalesce the international community around collective action.

This is not a new demand resulting from today’s crises. It has been exercised by previous Secretaries-General in their diplomacy and in their willingness to say difficult things at difficult times.

Dag Hammarskjöld did not simply administer the UN, he redefined the office during the Congo crisis, asserting the independence and authority of the Secretariat in the face of great power pressure. U Thant used backchannel diplomacy during the Cuban Missile Crisis to help de-escalate a confrontation that threatened global catastrophe. Javier Pérez de Cuéllar facilitated the end of the conflict in Cambodia and deployed one of the UN’s first multidimensional peacekeeping missions. Boutros Boutros-Ghali articulated an ambitious vision for preventive diplomacy in the post-Cold War era through the “Agenda for Peace.” Kofi Annan, confronted with the failures of Rwanda and Srebrenica, did not retreat into silence. He pushed the institution toward developing the Responsibility to Protect (R2P) and placing protection at the center of the UN’s normative framework. Ban Ki-moon presided over the largest expansion of the UN’s protection footprint through the deployment of multidimensional peacekeeping operations in Sudan, Congo, South Sudan, Central African Republic and Mali.

Across each of these tenures, the authority and relevance of the Secretary-General – and the UN itself – have ultimately been measured by the willingness and ability to respond to moments of acute vulnerability and looming catastrophe. Secretary-General António Guterres’s two terms have been marked by some of the gravest atrocity crimes of our time, including the devastating civil wars in Syria and Ethiopia, the invasion of Ukraine and three genocides (in Myanmar, Gaza and Sudan). While his statements have drawn attention to these crises, the political leadership required to generate a meaningful international response has too often been absent.

Take the current war in Sudan, for example. While various parts of the UN system have responded, with agencies like the UN High Commissioner for Refugees and the Office for the Coordination of Humanitarian Affairs working to address the catastrophic human toll of the war, the Secretary-General and his representatives have been limited in their ability to generate sustained political momentum and maintain consistent high-level attention. Humanitarian response, however essential, is not a substitute for political action or preventive diplomacy. This reflects a leadership approach that has been insufficiently bold or assertive.

Sudan’s conflict is complex and protracted, and the path to a democratic future is neither simple nor linear. But in the years preceding the current crisis, there were clear early warning signs that civil war was imminent. Instead of fully leveraging preventive diplomacy, reporting to the UN Security Council was heavily redacted, blunting the ability to act on those warnings.

Multiple political processes led by states and regional organizations have started and stalled without resolving the conflict in Sudan. What has been needed is a sustained political space, anchored by the Secretary-General, to secure a ceasefire and halt the trajectory of violence that has escalated to genocide and other grave atrocities. The UN is not the only actor responsible for “solving” Sudan or the many crises on the Security Council’s agenda, but it remains the most central. It is one of the few actors capable of bringing diverse stakeholders to the same table and sustaining a platform for engagement. This is not a moment for hesitation or for ceding space to others. Mediation is not an abstract process that one waits to be invited into; it must be created, shaped and led.

For years, the Secretariat has grown increasingly cautious in its engagement with member states, often in an effort to deflect criticism that it is too politicized. But this misses the point. The UN is inherently political. Politics is the arena in which it operates. Attempts to deny this reality do not produce neutrality. They produce hesitation and, in doing so, weaken accountability by obscuring the power dynamics that shape decisions. Leadership at this level cannot be about passively waiting for consensus; it requires a Secretary-General willing to seize the moment and present a clear, courageous vision for the path forward.

Agendas centered on human rights, the protection of civilians and the prevention of mass atrocities are not peripheral concerns. They are central to the UN’s identity and legitimacy. The Secretary-General, entrusted with providing early warning, should empower his representatives and staff to speak publicly and credibly about risks before violence erupts. Quiet diplomacy has its place, but at a time of mounting atrocities and deepening impunity, the world needs a Secretary-General who acts as a visible advocate for the most vulnerable.

The challenge extends beyond leadership at the top. It is also about how the institution understands itself and operates in practice. Creating the conditions for meaningful change is as important as the reforms themselves. Without a shift in institutional culture, reform efforts will remain temporary fixes, revisited time and again.

Over decades, a culture of bureaucracy, opacity and risk aversion has become embedded within the UN system. Too often, these are treated as a symptom to be managed rather than as root causes to be confronted.

Meaningful transformation cannot be imposed through technical adjustments alone. It must be driven from within, grounded in the values and principles that shaped the UN’s founding mission. Leadership is central to this shift. Where leadership is courageous, intentional and inclusive, culture can shift in ways that transform not only what the UN does, but how it does it.

This is not an abstract institutional concern. It goes to the heart of the UN’s relevance at a moment of profound strain. The sidelining of the UN in key global discussions, a broader crisis of multilateralism and a deepening financial crunch – forcing the organization to shrink its footprint and do more with less – are eroding its ability to deliver. This is also a moment marked by inter- and intrastate conflicts, where the risks to civilian populations are acute and escalating. It is precisely in such moments that the UN is most needed – as an arbitrator of peace and a convener capable of shaping political pathways out of crisis. Restoring confidence in the institution requires more than procedural reform, it demands a renewed capacity to act across its peace and security and human rights mandates. Without this shift, the UN risks further diminishing its relevance at precisely the moment it is most needed.

In order to secure the future of the UN, the next Secretary-General should lead through three guiding principles:

Courageous leadership. The next Secretary-General must exercise moral and political courage, not just managerial competence. This means speaking clearly about emerging risks, advocating consistently for prevention and protection and confronting powerful states when their actions undermine the Charter and international law.

Transparency and integrity. Trust between the Secretariat, member states and civil society cannot be built through opacity or overly managed engagement. It requires candor, institutional honesty and a willingness to share information in ways that are meaningful and actionable, while fostering a culture of accountability within the system itself.

Protection as a core function. The UN must reclaim protection not as one priority among many, but as its defining purpose. Preventing mass atrocities, protecting civilians and defending human rights are central to the institution’s legitimacy and cannot be sidelined in moments of political difficulty. The UN cannot be effective while attempting to sidestep politics. The challenge is not to avoid political realities, but to engage them with principle and sustained commitment. The choice facing the next Secretary-General, therefore, is not simply about leadership style. It is about whether they are willing to fully inhabit the role they are entrusted with.

For many of us drawn to international policy, the United Nations was never defined by its bureaucracy, but by its leadership – leaders who spoke with clarity, took principled positions and understood that speaking truth to power was not optional. That is the standard the incoming Secretary-General must meet. The office must once again be politically engaged, normatively grounded and strategically assertive.

Whether the UN catalyzes its own renewal and that of multilateralism will depend on whether its next leader is prepared to lead not cautiously, but courageously; not quietly, but visibly; and not as an administrator alone, but as the advocate the Charter demands.