Emmanuel Macron and Donald Trump attend a joint press conference at the end of the G7 summit in France.Christian Hartmann / Reuters

Shortly after signing the Declaration of Independence, Benjamin Franklin, a Founder of the republic and America’s first diplomat, famously told his fellow revolutionaries: “We must, indeed, all hang together or, most assuredly, we shall all hang separately.”

This week, leaders and diplomats, activists and CEOs from around the world will gather in New York for the annual UN General Assembly. From the halls of the United Nations to the hotels of Midtown Manhattan, the issues on everyone’s lips will be climate change, the trade war, tensions in the Gulf, or any of the world’s conflicts and humanitarian crises. But the question on everyone’s mind will be whether the multilateral system that’s supposed to address these challenges (albeit often imperfectly) has itself become a dead man walking. This fear has prompted a desperate attempt by a group of countries led by Germany and France to revive the spirit and practice of international cooperation by launching the Alliance for Multilateralism on September 26. Almost certain to be conspicuously absent (and the implicit reason for this initiative): the United States of America.

The very government that on its own soil founded and largely sustained the multilateral world we have known since 1945 has effectively abandoned it. Donald Trump withdrew from the Paris climate accord, the Iran nuclear deal, and the Trans-Pacific Partnership. His administration has defunded and disengaged from the United Nations while paralyzing the World Trade Organization. And he’s disparaged NATO allies and questioned the alliance’s core commitment to mutual self-defense.

Though Trump’s rhetoric and actions in office have accelerated and exacerbated the fraying of the multilateral system, the crisis of multilateralism has much deeper roots as the UN and Bretton Woods Institutions approach or embark on their 75th years. Richard Gowan, an expert on the UN, sees three crises in particular: first, a crisis of power in which the shift of power from the U.S. to China has diminished America’s ability to shape the international agenda and drive collective action; second, a crisis of relevance in which antiquated and sometimes sclerotic international institutions struggle to tackle the critical global challenges, from Syria to cybersecurity; and, third, a crisis of legitimacy as frustrated regional powers and nationalist leaders withdraw from multilateral organizations or erode them from within. In this depressing brew, Gowan, who is with the International Crisis Group, sees an opportunity for the EU to become a third pole in geopolitics (along with the U.S. and China) as the practical champion of multilateralism. Considerable thinking has gone into how middle powers from the Americas to Europe to Asia can bolster the so-called rules-based order. The €64,000 question, however, is whether any of this has a prayer without the United States. Almost certainly not.

If you listen to Trump-administration officials, 2020 candidates, members of Congress, and pundits, there seems to be only one bipartisan consensus in Washington: We are living in a new era of great power competition. For the United States to win (whatever that means), it must compete—economically, militarily, technologically, and politically. Yet this paradigm, fed by President Trump’s zero-sum worldview and the anti-China hysteria sweeping Washington, has buried a key to America’s once and future success in the global arena: cooperation.

After the devastation of the Second World War, U.S. policy makers looked for a different way to reconstruct global order and drew on America’s own political culture of consultation and compromise, economic openness, and the rule of law as a model. A multilateral spasm ensued, and the UN, the World Bank, the IMF, the GATT (later the WTO), NATO, and eventually the European Union were born.

These institutions and America’s multilateral leadership style were essential to winning the Cold War—the last great power competition. Why? Because Washington attracted countries and people to it by convincing them that America was out for more than itself. How? By (mostly) upholding its commitments, following global rules, defending friends and allies, finding common ground with foes, and practicing painstaking consultative diplomacy.

This produced an unprecedented era of relative global peace and prosperity, but not without some costs and constraints. The United States had to follow the same rules as everyone else, even though it was the most powerful country. Washington shouldered a substantial, perhaps disproportionate load, politically and financially, for supporting international organizations and alliances; and allies and partners did free-ride on occasion. And while many Americans prospered, many also lost their jobs, and sometimes their communities, as an open global economy enabled companies to find cheaper labor and less regulation overseas. Trump has used these downsides to drive a wedge around multilateralism and make America isolationist again. His administration has denigrated international cooperation as weakness and deliberately damaged the multilateral system America built. It has done so at great peril.

Since 1945, the world has largely played America’s game, by America’s rules. But now Washington is deciding to play its rivals’ geopolitical game. Competitive zero-sum thinking comes naturally to Moscow and Beijing (and Trump), less so to Americans. As George Kennan warned in his Long Telegram from Moscow in 1946, at the dawn of the Cold War: “The greatest danger that can befall us in coping with this problem of Soviet communism, is that we shall allow ourselves to become like those with whom we are coping.”

Kennan also advised, “We must formulate and put forward for other nations a much more positive and constructive picture of the sort of world we would like to see than we have put forward in the past.” That America has always stood for and believed in more than itself—and consistently articulated an affirmative, optimistic vision for the world—has been the secret sauce in its global leadership for the past 75 years. What and who will bound and buffer this new competition? An affirmative American vision with robust engagement in international organizations that can provide a diplomatic arena for great power politics to play out nonviolently would certainly help.

But even more problematic is the fact that an obsession with great power competition complicates international cooperation on shared global threats. Will great power competition prevent the most destructive weapons from falling into the most dangerous hands? Keep deadly pandemics from ravishing the world? Protect U.S. workers from races to the bottom? Mitigate the worst effects of new technologies? These severe, urgent, and potentially existential threats demand cooperation among the great powers. They also happen to be the ones that Americans care most about, much more than China and Russia. As UN Secretary-General António Guterres put it recently, “Multilateralism is under fire precisely when we need it most.” Creating the political will and space to cooperate with rivals and even enemies on such threats, as the U.S. and the U.S.S.R. did on arms control during the Cold War, may be the most critical geopolitical challenge of our time. And it is exponentially harder in a world of defunct multilateral institutions from which America is disengaged.

This is not to suggest that America should ignore great power competition or will it away. As the past 30 months have put into stark relief, multilateralism—the core American geopolitical asset Trump has so gleefully discarded—is a force multiplier essential for success in an era of increased competition. Just consider how Trump has botched his own priorities by eschewing a multilateral approach:

On trade, with his admirable willingness to countenance more friction in U.S.-China relations, Trump could have built a coalition inside and outside the WTO to redress China’s rule-skirting, predatory trade practices, and intellectual-property theft. As Bill Reinsch, Scholl Chair in International Business at the Center for Strategic and International Studies, told me, “China has proven itself susceptible to multilateral pressure. It doesn’t like to be isolated. But because the U.S. has approached the China trade problem unilaterally, China can hold firm and get away with presenting itself as the defender of the global trading system.” Instead, Trump antagonized allies by imposing steel and aluminum tariffs on them, threatening auto tariffs, and paralyzing the WTO dispute-resolution mechanism. Rather than solving the China problem, Trump’s tariffs will end up costing the average American household more than $1,000 in 2019 and even more in 2020.

On Iran, the Trump administration bet that withdrawing from the nuclear pact and launching a maximum-pressure campaign of painful sanctions would force Tehran into a “better” deal. That has not happened. President Hassan Rouhani has publicly ruled out talks until sanctions are lifted. As Adam Szubin, former acting Treasury Department undersecretary for the Office of Terrorism and Financial Intelligence, told me, while unilateral U.S. financial sanctions can impose significant pressure on a country, multilateral sanctions—coordinated by the world’s financial or trading powers or adopted by the UN—usually have more “bite.” They also reduce the ability of the sanctioned party to circumvent sanctions through other countries and have a powerful stigmatizing effect by demonstrating the isolation of the sanctioned party in a way that unilateral sanctions cannot.

Finally, on Russia, Trump has ignored his intelligence agencies’ warnings about Moscow’s aggressive, persistent political interference in the United States and Europe. Instead, he has treated Russian President Vladimir Putin with kid gloves rather than mobilizing allies to deter Russia’s destabilizing behavior. As Laura Rosenberger, the director of the Alliance for Securing Democracy at the German Marshall Fund, told me, “Democracies rise and fall together. Cracks exploited in one threaten them all.” In 2018, the G7 made a commitment to defend democracy from foreign threats, but much more cooperation is needed, including in the financial realm, to build resilience and ultimately deter political interference from Moscow and others who seek to tear democracies apart from the inside. While Trump’s administration identifies Russia as a primary threat to the United States, he himself has approved only modest sanctions against Russia, weakened NATO’s credibility, and even suggested that Moscow be readmitted to the G7.

Trump may not have put the multilateral system on life support, but he is trying to pull the plug on it. As authoritarians rise, the climate changes, technology advances, and too many are left behind, Ben Franklin’s existential call to cooperate is as vital for the United States in the global arena of 2019 as it was for the American colonies in 1776.

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