In the face of U.S. President Donald Trump’s Greenland spectacle, liberal-minded U.S. politicians and foreign-policy experts are now openly pinning their hopes for the free world on a stiffening of the European spine. California Gov. Gavin Newsom, for one, let loose this week in Davos, Switzerland, warning foreign governments against diplomacy with Trump: “He’s a T. rex. You mate with him or he devours you.”

Rooting for the other guy in a dispute with the United States does not come naturally to former and would-be U.S. foreign policymakers. But Washington’s abdication of its global leadership role—and its unprecedented threats against NATO allies in its quest to take over Greenland—has begun to turn the tables. Although Trump may have blinked on Greenland for now, there is a growing sense among this set that only Europe’s unflinching resolve will force the White House to take its commitment to international norms more seriously and keep the trans-Atlantic partnership alive to fight another day.

In the face of U.S. President Donald Trump’s Greenland spectacle, liberal-minded U.S. politicians and foreign-policy experts are now openly pinning their hopes for the free world on a stiffening of the European spine. California Gov. Gavin Newsom, for one, let loose this week in Davos, Switzerland, warning foreign governments against diplomacy with Trump: “He’s a T. rex. You mate with him or he devours you.”

Rooting for the other guy in a dispute with the United States does not come naturally to former and would-be U.S. foreign policymakers. But Washington’s abdication of its global leadership role—and its unprecedented threats against NATO allies in its quest to take over Greenland—has begun to turn the tables. Although Trump may have blinked on Greenland for now, there is a growing sense among this set that only Europe’s unflinching resolve will force the White House to take its commitment to international norms more seriously and keep the trans-Atlantic partnership alive to fight another day.

Trump’s foreign-policy buccaneering foretells disaster for those who recognize that the United States has thrived in a global order largely of its own making, that rules and institutions fortify U.S. prosperity, and that alliances help keep the country safe. If Trump continues on his current trajectory, it’s likely that the global trade system will evolve in ways that circumvent the United States, long-standing allies will hew closer to China, self-inflicted tariffs will hinder U.S. businesses, foreign-policy institutions will be hollowed out, and the U.S. military will be weakened by overextension and eroded morale.

Canadian Prime Minister Mark Carney’s viral Davos speech, which pronounced the U.S.-led world order dead, suggests it may already be too late to save the only global system that any policymaker alive today has ever known. Fast-moving global realignments are hedging against a volatile Washington, with Canada strengthening ties to China, the European Union driving toward a sweeping trade pact with Latin America, and Japan deepening defense cooperation with Europe. Pension funds and investors are not far behind. While Trump can sometimes be spooked by the stock market, he stated earlier this month in an interview with the New York Times that the only force that can stop him is his “own morality” and “own mind.”

While foreign-policy thinkers and watchers once held out hope that Secretary of State Marco Rubio and internationalist Republicans on the Hill might emerge as voices of reason with some sway over Trump, that increasingly seems like wishful thinking. The question now becomes what could possibly bridle Trump.

The seasoned advisors and military generals who once restrained Trump’s most aggressive instincts, such as former Defense Secretary James Mattis and former Joint Chiefs of Staff Chair Mark Milley, are long gone. Now that the Republican-controlled Congress has acceded to Trump’s adventures in the Caribbean, Venezuela, and Syria, there is little hope that it will pump the brakes on gambits such as the attempted acquisition of Greenland, despite what diplomats, markets, and most Americans see as clear White House overreach. Midterm elections may change the calculus, but those are still more than nine months away.

By process of elimination, if anything can stop Trump in time, it may be foreign nations joining forces to thwart him.

Trump may have shifted gears for now on Greenland, but Europe still faces grave questions about how best to engage him when it comes to Ukraine, the Middle East, and other global hot spots. Those who delighted at the idea of TACO—“Trump Always Chickens Out”—have been forced to admit that he only sometimes backs off. Whether bunker busters in Iran or the capture of Venezuelan President Nicolás Maduro, it is clear that Trump often follows up (TOFU, if you will).

Trump often does seem to back down in contests of will when opponents refuse to yield. He threatened heftier sanctions on Russia over its war in Ukraine, only to abandon a series of deadlines when Russian President Vladimir Putin did not flinch. When Beijing upped the ante and retaliated against punishing U.S. tariff measures in April, vowing to “fight to the end,” Trump swiftly retreated, cutting a deal.

While authoritarians have gone toe-to-toe with Trump, most would-be defenders of the values-based international order have been far more reticent. Much as they yearn to see Europe play hardball with Trump, the U.S. foreign-policy establishment understands why that would be risky: Europe’s deep dependency on Washington as a trading partner, arms supplier, and security guarantor would take years, if not decades, to unwind.

Leaders such as NATO Secretary-General Mark Rutte and British Prime Minister Keir Starmer have leaned into flattery, hoping to insinuate themselves into Trump’s confidence because they know they cannot count on him as a rational actor. They approach him as a lion tamer would—with cajolery, rewards, calming words, and, above all, an instinct for self-preservation.

Observers in the United States, however, have watched Trump betray even some of his most fawning loyalists in Congress and the business world—not to mention Venezuelan opposition leader María Corina Machado. U.S. foreign-policy thinkers and practitioners want the Europeans to roar back because they believe that Trump smells fear and responds above all to power. They have also come to see that, to survive an increasingly hostile world, liberal institutions and values will need undaunted defense and, even more so, offense that pushes back against the forces of authoritarian corrosion. Their hope is that if Trump really believes that U.S. allies have the cojones to abandon Washington and go their own way, the risk of practical and reputational damage to his administration could be chastening.

For the U.S. foreign-policy establishment, it is hard to imagine a world in which onetime U.S. allies have reluctantly concluded that they are better off outside the orbit of a menacing Washington. No matter the issue—stopping a war, containing terror, battling a pandemic, or managing the future of artificial intelligence—the United States’ first port of call has always been to mobilize friends across the globe.

U.S. policymakers who believe in this system are now begging for tough love—a determined intervention to convince a wayward Washington that its rhetoric and tactics will leave the United States weakened and alone. The Trump administration has been unwilling to hear that message from legions of former officials, military leaders, policy experts, and analysts who have joined a chorus of rising alarm at home.

Among the lingering hopes that some force will arise to rein in a self-destructive United States is the prospect of Washington’s closest friends drawing a line in the sand and daring Trump to cross it.