If America abandons the liberal international order it created, can that order still endure?

This has been the central geopolitical question posed by Donald Trump’s presidency. So far, longtime U.S. allies have been working to fill the void created by the retreat of American leadership, and thus to prevent the erosion of a system that has served so many so well for so long. Yet their efforts cannot be more than a temporary solution to the crisis of global stewardship that Trump has created.

From the time Trump announced his candidacy in 2015, his visceral distaste for the international system the U.S. shaped after World War II was obvious. Generations of previous presidents saw the promotion of a geopolitically stable, economically open, ideologically liberal world order as a form of enlightened self-interest—a strategy that would allow America to remain secure, prosperous and free by helping others become secure, prosperous and free.

Trump, however, has long seen this order-building project as a geopolitical fool’s errand that allows other countries to free-ride on American labors. “We’ve made other countries rich while the wealth, strength, and confidence of our country has disappeared over the horizon,” he said in his inaugural address.

Despite the best efforts of many of his advisers, including Secretary of State Rex Tillerson and Secretary of Defense James Mattis, Trump has thus taken dead aim at key aspects of America’s own international order.

He has harangued and bullied U.S. allies, and withdrawn or threatened to withdraw from numerous free trade agreements. He has derided the importance of human rights and democratic values, and sought to make common cause with countries—namely Russia—that most threaten American interests, allies and ideals. Not least, he has revived narrowly nationalistic rhetoric and ideas—encapsulated in his “America First” slogan—that sound to many observers like the very antithesis of inclusive, positive-sum global leadership.

Fortunately, America’s closest partners have not simply stood still as U.S. statecraft has taken this ominous turn.  

Japan and Australia responded to the U.S. withdrawal from the Trans-Pacific Partnership by launching a surprisingly effective bid to sustain that agreement without Washington’s participation. (So effectively that Trump has made noises about re-considering U.S. involvement.)

Likewise, Japan and the European Union agreed to negotiate a major free trade pact. In global security affairs, France and Japan are now reportedly planning naval exercises in the South China Sea to show support for freedom of navigation in the face of a continuing Chinese challenge. Meanwhile, the EU, led by Germany and France, has outlined ambitious plans to improve European defense cooperation, in part as a hedge against a future in which U.S. commitments no longer seem so ironclad. Finally, the rest of the world is continuing to implement the Paris Accords on climate change, despite Trump’s decision to withdraw.  

This behavior should be encouraging to those who value the U.S.-led international order, precisely because it is the ultimate testament to the success of that order. That U.S. allies see such great value in this system demonstrates just how attractive a world Washington has created in the decades since World War II. They are conducting a critical holding action—they are trying to keep the liberal order as healthy and stable as possible until Washington once again emerges as its chief defender.

All this will help keep the positive dynamics that U.S. leadership has traditionally fostered—openness, security, international cooperation—from being swamped by more negative trends like protectionism, instability and parochial nationalism, at least in the short term.

Yet neither the liberal order nor the U.S. can thrive in the long term without stronger American engagement, for three key reasons.

First, America’s allies may be defending the liberal order, but they are not necessarily doing so in the way that Americans might prefer. It is laudable that the EU, Japan and other countries are pushing back against protectionism, but the agreements they conclude will be far less favorable to U.S. interests than they would be if Washington was at the table and setting the agenda.

American exporters are already worried, for instance, that an 11-member “rump TPP” will put them at a competitive disadvantage by creating a more integrated economic zone from which the U.S. will be excluded. Trump may think his foreign policy will allow the U.S. to cut better deals, but it is actually giving other countries incentive to cut deals at America’s expense.

Second, Trump’s withdrawal is not just creating space for America’s democratic allies. It is also clearing the field for authoritarian actors—namely China—whose goals often run contrary to U.S. interests. As I recount in my new book, “American Grand Strategy in the Age of Trump,” Chinese leaders have cleverly positioned themselves to benefit from Trump’s nationalistic turn. The have accelerated geopolitical and geo-economic projects, such as the Regional Comprehensive Economic Project and the Belt and Road Initiative, which are meant to weaken the U.S.-led order by creating China-centric alternatives.

They have also exploited Trump’s global unpopularity by portraying China as the new world leader on issues such as climate and globalization. Some of these claims are risible—Beijing’s foreign economic policy is mercantilist to its core, and China has long been adept at reaping the benefits of the liberal economic order without obeying its rules. But U.S. withdrawal is nonetheless giving the global initiative to actors threatening as well as benign.

Finally, although U.S. allies have sometimes bristled at descriptions of America as the “indispensable nation,” the hard reality is that there are limits to what they can achieve without Washington. No one, not even most Europeans, expects great breakthroughs in European defense cooperation in the age of Trump. This is because EU military integration still suffers from its perpetual problem—it has all the liabilities of a complicated multilateral undertaking without the benefit of having the U.S. there to plug the inevitable gaps.

Likewise, the downsized TPP and the EU-Japan trade agreement are positive developments, but it is hard to imagine that a truly liberal international economy will long endure if the world’s two largest national economies—the U.S. and China—take protectionist stances.

In short, longstanding U.S. allies can buy time for Washington to get back in the game—but they can’t do much beyond that. If Atlas doesn’t take up his burden again sometime soon, the world he formerly supported will surely start to crumble.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.