What if the United Nations didn’t exist? It’s a question easily answered, because for nearly all of human history, it didn’t. History “teaches us that order in international relations is the exception, rather than the rule,” Kevin Rudd, the former Australian prime minister, writes in a new report on the uncertain future of the UN. “Since the rise of the modern nation-state, both prior to and following the Peace of Westphalia in 1648, disorder has been the dominant characteristic of inter-state relations.” We tend to think of the United Nations as just another part of the global furniture. But it’s actually a recent addition.

Over the last 500 years, Rudd notes, “there have been four major efforts in Europe to construct order after periods of sustained carnage”: in 1648, after the Thirty Years’ and Eighty Years’ wars; in 1815, after the French Revolutionary and Napoleonic wars; in 1919, after World War I; and in 1945, after World War II. “The first three of these ‘orders’ have had, at best, patchy records of success. The jury is still out on the fourth.”

That fourth attempt—the United Nations—is now in a period of transition as the race for the organization’s top job nears its end. It’s the most important election nobody’s ever heard of, and hinges on secret straw polls at the Security Council that could yield a result within the month. Rudd, whose name was once mentioned among the potential contenders to replace Ban Ki-moon as secretary-general, is not in the mix. (Australian Prime Minister Malcolm Turnbull refused to nominate him.) But the study he released this week as chair of the Independent Commission on Multilateralism is a guide to the global forces that will confront whoever takes the job—including the possibility that the United Nations itself, though it’s unlikely to collapse anytime soon, might gradually atrophy to the point of irrelevance.

The concept of entropy in international relations is instructive here, Rudd writes: “Under this argument, any international order, once established, is immediately subject to the natural processes of decline and decay, ultimately resulting in a return to disorder.”

There is “growing evidence of nation-states walking around the UN to solve major problems and then perhaps coming back to the UN when it’s all done as some sort of diplomatic afterthought,” Rudd told me. The United Nations continues to establish rules for how people and states should conduct themselves in the world. “The problem is, if you simply set norms and don’t do anything about the execution of those norms, as the international agency given that function back under the charter of 1945, then you start to lose complete relevance over time.”

I asked Rudd whether the remaining secretary-general candidates were advocating the kinds of reforms he’d like implemented at the United Nations. “I ... understand that in a competitive selection process such as this, many candidates are going to choose to be publicly diplomatic about the sort of problems the UN faces,” he responded. Presumably he himself can be less diplomatic, now that he is no longer auditioning to be the world’s chief diplomat.

“We are facing the biggest set of external changes and challenges to the global order since 1991,” following the fall of the Soviet Union, Rudd told me. “Over the last 25 years, we haven’t seen anything comparable to the current state of great-power relations. We haven’t seen anything comparable to the current intensity of the globalization process. We haven’t seen anything comparable to the emergence, for example, of terrorism as a mainstream threat to many societies across the world. These are new phenomen[a]. Each age has had its own new phenomenon. But in a quarter of a century, which is a long time [for] an institution that only has a 70-year history, it’s a set of circumstances which should cause us to act.”

Rudd’s report includes numerous prescriptions for reinventing the institution, from striking a new international agreement on resettling refugees to more rigorously measuring the results of UN initiatives. The United Nations, Rudd told me, is much better at reacting to crises than anticipating and preventing them. He proposes investing in a policy-planning staff that can analyze global trends several years into the future, and in what he calls “preventive diplomacy.” As an example, he cited the UN’s appointment in 2013 of the former president of East Timor, Jose Ramos-Horta, as a special representative to the West African nation of Guinea-Bissau, which had just experienced a military coup; within roughly a year, Ramos-Horta had helped forge enough political consensus for elections to be held. Prevention could also mean, for instance, prepositioning food aid in countries at the earliest warnings of famine, or tracking unemployment patterns to predict where violent extremism could emerge.

But it’s Rudd’s diagnosis of what’s ailing the United Nations that is particularly notable. The rise of non-state actors such as terrorist groups, intensifying rivalries between the United States and Russia and China, and a fierce backlash against globalization are all challenging the “assumption of recent decades that the dynamics of greater global integration were somehow unstoppable,” he writes.

This is an urgent problem, Rudd argues in the report, because despite its many failings, the United Nations “is the worst system of international governance except for all the others.” Among other things, he writes, the UN has helped avert another world war; played a role in drastically reducing the share of the global population living in extreme poverty; created a system of dispute-settlement institutions to counteract the “long and malignant history of territorial and trade disputes” sparking international conflict; staved off the “all-out proliferation of nuclear weapons” that looked so likely in the early 1960s; and provided humanitarian relief to vulnerable populations that, before the advent of the UN, were often “simply left to die.”

But recent years have brought worrying signs of weakness, according to Rudd. The UN wasn’t a participant in international talks to restrict Iran’s nuclear program, he points out, even though one of its institutions, the International Atomic Energy Agency, was tasked with helping implement the resulting agreement. The UN has been similarly absent from efforts to address other major security challenges like the war in Ukraine and the acceleration of North Korea’s nuclear program. It sluggishly responded to the Ebola epidemic in West Africa, and has bungled the refugee crisis in the Middle East and Europe. And it has failed to prevent mass atrocities and resolve chronic conflict in countries like South Sudan and Syria. The UN’s role in spreading a cholera epidemic in Haiti through the unsanitary practices of its peacekeepers—a role the organization only recently acknowledged, after years of denials—has further tarnished the institution’s image.

Meanwhile, escalating tensions between the United States and China over cyberspace and territorial disputes in the East and South China Seas, and between the United States and Russia over NATO expansion and Russian actions in Ukraine, threaten to make the UN Security Council—where all three countries can veto resolutions as permanent members—as dysfunctional as it was during the Cold War.

Rudd adds that as terrorism spreads around the world, becoming the top security priority for many countries, the United Nations has failed to adequately respond to, or even define, the problem, which doesn’t easily fit within the UN’s state-centric view of the world. “[T]he UN has been unsuccessful in confronting the question of state-funded terrorist activity, in dealing with the political, economic, and social root causes of terrorism, and in agreeing and promulgating a global narrative on countering violent extremism,” he writes.

Most striking is Rudd’s assessment of the predicament national political leaders find themselves in, given that he was, not so long ago, one himself. These leaders, he writes, “are no longer, in substance, capable of delivering self-contained, national solutions to the problems faced by their people,” which “contributes to a related crisis of legitimacy for the international institutions nation-states have constructed.”

This crisis of legitimacy has direct bearing on the future of the United Nations. Countries, Rudd writes, are increasingly split between “globalists” and “localists,” particularly amid feeble economic growth following the 2008 financial crisis:

This, in turn, is beginning to create a fertile political space for more extreme political movements, either of the far left or the far right, driven by populist protest against the broad, globalizing consensus of the mainstream political center that has by and large prevailed over the last few decades.

Protectionist sympathies are therefore on the rise, as are xenophobic approaches to migration and, more broadly, a political impetus to “throw up the walls” against the forces of continuing globalization. This, in turn, is breeding new nationalist and mercantilist movements, which vilify not only their own governments, but also the regional and global institutions of which their governments are members and to which too much sovereignty, in their view, has already been ceded.

The net result is a fracturing and failure of national politics. We are seeing weakening national support for regional institutions such as the European Union. Global institutions such as the UN are seen as even more remote from local concerns.

On a daily basis, we hear reports of the United Nations succeeding with this or that, or failing to do this or that. But we rarely pause to consider what these successes and failures say about the relevance of the UN in the world today—and what the world would look like without it. Rudd’s report can ultimately be read as a plea for something pretty basic: to not take the United Nations for granted.