PRINCETON • With global leadership now in question, the Group of 20's (G-20's) summit in Hamburg tomorrow and on Saturday could be the group's most tense meeting. The summit process long predates the G-20's founding in 1999. It was originally designed, in the 1970s, to align major economies' domestic policies, thereby reducing uncertainty. But domestic politics have now created a new type of uncertainty.
Whereas the international community isolated Russia at the G-20 Brisbane summit in 2014, the US has isolated itself this year. After making a blustering appearance at the Group of Seven (G-7) Taormina summit this May, President Donald Trump announced that he was withdrawing the US from the 2015 Paris climate agreement. In response, European G-7 leaders, with the notable exception of British Prime Minister Theresa May, have signed a declaration condemning Mr Trump's position.
After serving as the main architects of the United Nations system and the post-1945 international order, the United States and the United Kingdom now seem intent on reversing that legacy.
Since Mr Trump's election and the Brexit referendum last year, both countries have embarked on an inconsistent and highly contested political path away from openness and multilateralism.
Their trajectories, while erratic, have been remarkably similar.
Indeed, many saw the Brexit referendum as a precursor to Mr Trump's election. Like the Leave campaign, Mr Trump has tapped into voters' fears about immigration. And, like Mrs May's post-referendum government, the Trump administration has floundered in office. In both cases, a poorly conceived campaign has caught up to the victors. And, as the winners have started to look like losers, the left-wing populism of more authentic politicians, such as Senator Bernie Sanders in the US and Labour Party leader Jeremy Corbyn in the UK, has become increasingly popular.
The Trump and May governments also share striking similarities in international outlook. Both want to renegotiate international deals, such as trade treaties or, in the case of the British, their relationship with Europe. But the basis for such renegotiations is as unclear as it is contradictory.
As American and British workers have come to associate globalisation with job losses and inequality, they have demanded more protection. But protectionism usually comes at a high cost to consumers, especially to low earners. In fact, a great deal of statistical evidence suggests that lower-income groups tend to benefit the most from trade liberalisation.
Against this backdrop, any effort to change existing arrangements will probably entail striking narrow deals and severely penalising select imports. The risk is that retaliatory measures by other countries will trigger a vicious circle of protectionism and deglobalisation.
In the post-war period, countries became increasingly linked through government and administrative agencies, multinational corporations and financial institutions, all of which created an environment that was conducive to cooperation.
Today, however, the mechanisms of globalisation are already being eroded. Professional bureaucracies - not least the US Foreign Service - are being cut back. Corporations and media outlets are routinely admonished to be more patriotic. Finance is being segmented and renationalised. And soft-power institutions, such as Hollywood and universities, are now mired in culture wars.
American and British universities have long topped world rankings, and regard themselves as global institutions with a global responsibility. The president of Harvard University, Professor Drew Faust, often enthuses about her institution's international role; and Princeton University recently changed its motto from "In the nation's service and the service of all nations" to "In the nation's service and the service of humanity".
But, in recent years, cosmopolitanism and global outreach have provoked a backlash. Consider Mrs May's memorable words before the Conservative Party conference last October: "If you believe you're a citizen of the world, you're a citizen of nowhere. You don't understand what the very word 'citizenship' means."
With the post-war spirit of universality in retreat, the old globalisation will need new leadership and a new approach to multilateralism and soft power.
This realisation has, inevitably, led China and Europe - specifically, Germany - to see themselves as the new defenders of the global order.
In fact, China and Germany are increasingly aligned on many key issues. Both have reaffirmed their commitment to reducing carbon dioxide emissions under the Paris accord, and both object to President Trump's obstructive crusade on behalf of the coal industry.
There is also a clear Chinese-German alliance forming to oppose trade protectionism. Recently, after Chinese President Xi Jinping described protectionism as akin to "locking oneself in a dark room", German Chancellor Angela Merkel praised his words as "very memorable".
Now that Germany's G-20 presidency is underway, German leaders have been exploring how their country might promote globalisation in America's stead. But Germany is simply too small to act as a hegemon, and its position within the euro zone is still being strained by the legacy of the 2008 financial crisis.
China, too, would encounter obstacles in pursuit of global leadership. Its financial sector is still relatively underdeveloped and prone to crises. Its large infrastructure initiative, One Belt, One Road, will create new dependency problems and exacerbate existing rivalries in Asia. And, finally, the prospect of Chinese leadership will raise fears about the fate of democracy.
At the heart of anti-globalisation critiques in rich countries has been a call for more democracy, not less.
To be sure, some of the ingredients for a new form of global leadership are there: China has great universities that are rapidly improving and Germany has a strong democracy built on federal principles and anchored in a vision of European integration.
But without every ingredient, the recipe will not be complete.
The American century was based on strong domestic institutions, shared values, and a vibrant cultural life. Globalisation based on economic logic alone will never work.
- The writer is professor of history and international affairs at Princeton University and a senior fellow at the Centre for International Governance Innovation.