I cannot recall a time during the past 75 years when there has been such a massive accumulation of major and minor shocks. The world today is dealing with intensifying climate change, a pandemic, major wars, surging inflation, disruptions to international trade and supply chains, and acute food and energy shortages.

A significant share of this turmoil stems from new (and renewed) rivalries between major powers. This has had highly visible and chaotic consequences, epitomised by Russia’s war of aggression in Ukraine. One does not have to be a prophet of doom to foresee that the conflict will be one act in a longer tragedy. In East Asia, China’s claim to Taiwan also threatens to lead to military escalation. And in the Middle East, Iran’s ongoing nuclear programme could all too easily trigger a major military conflict.

In short, we are witnessing the denouement of the Pax Americana that underpinned international relations for more than 70 years following World War II. After emerging as the victor in both of the 20th century’s world wars, the United States went on to win the ensuing Cold War. During that time, it guaranteed peace and stability in Europe—which had been left largely destroyed in 1945—and laid the foundations for new multilateral systems of trade and international law, established under the umbrella of the United Nations, whose membership expanded as a result of decolonisation. But with the rise of China and others, Pax Americana—which certainly wasn’t perfect—has given way to a more multipolar reality.

Particularly since the start of this century, the world economy has been undergoing a fundamental technological transformation. Digitalisation and artificial intelligence are radically restructuring advanced economies and rebalancing political power globally. Since the 2008 financial crisis, global conditions have become more chaotic, revealing fatal flaws in Western assumptions. Europe succumbed to the illusion that an energy partnership with Russia would secure peace and stability on the continent. And US leaders mistakenly believed that China’s inclusion in the World Trade Organization and other multilateral arrangements would inevitably lead to its democratisation.

In both cases, Western leaders were blind to Russian and Chinese leaders’ strategic intentions and objectives. They were so confident in the universal attractiveness of their own civilisational models that they failed to anticipate the political consequences of the economic dependencies they had accepted. The bill for this naiveté is now coming due, and it will be large.

China has quickly become a technological rival to the West, and particularly to the US, which is not something that the Soviet Union could ever claim, even at height of the “Sputnik shock.” It remains to be seen where this new phase of systemic global competition will lead; but it is safe to say that China will be a tough nut to crack. Moreover, the new great-power contest will be fought out under completely new global conditions. Covid-19 and climate change have fundamentally altered the global economic and political calculus and will continue to do so.

If humanity fails to reduce greenhouse-gas emissions at the pace necessary to keep global warming in check, it will be heading into an era of irreversible and potentially uncontrollable global crises. Worse, owing to the new global competitive dynamics, major powers will head in the direction of intensified confrontation, even though the challenges we face demand closer cooperation. This is the real tragedy of Russian President Vladimir Putin’s war: Beyond its wanton destruction and unspeakable human suffering, the Ukraine crisis is costing humanity precious time that it does not have.

One last crisis should be mentioned here. Amid all the global chaos, the US also has deep domestic problems that cast doubt on its future as a stable, functioning democracy. On January 6, 2021, the country experienced its first-ever coup attempt. As the House January 6 Committee has shown, Donald Trump sought to overturn the 2020 election by intimidating state election officials, arranging for “fake” Electoral College slates, and ultimately inciting a violent mob to storm the US Capitol. Will American democracy prove resilient enough to prevent something like this from happening again, or will Trump or a Trump-like figure succeed where the January 6 “trial run” failed?

That question will be decisive, not only for the US and its democracy, but also for its allies and the future of humanity more broadly. The 2024 presidential election may be the first one ever to have direct civilisational and planetary consequences. It is no accident that the world’s fate in the 21st century will be decided in its oldest democracy, and in the country that has underwritten the international order for the past 75 years.

—Project Syndicate