Sadly, with the exception of the U.S., much of the West is sunk in decline. A generation of poor performance in the European Union and Japan means that America’s traditional partners bring less and less to the table each year. Japan seems to be undergoing an awakening. But many of our most important European allies are contending with three decades of economic, political and strategic failure.

Economically, our European partners and friends are failing the test of the digital age, generating neither the new technologies nor companies that the 21st-century demands. Their embrace of ruinous climate policies reduces their competitiveness. Their NIMBYism throttles growth, and their unsustainable welfare states further diminish their prospects.

Politically, our friends haven’t succeeded in making the EU great. Individual European states are too small to have much effect on global events, and when they try to act together, they punch below their weight. The EU bureaucracy moves too slowly and often with too many reservations and compromises to maintain Europe’s place among leading global actors. Meanwhile, partially as a result of a massive failure to manage migration policy and its consequences, the political establishment in country after country is losing ground to radical movements, sometimes on the left but more often on the right.

Strategically, the failure is even more dramatic. Europe is more vulnerable to Middle East disorder, Russian aggression and predatory Chinese economic policies than the U.S. is, but its responses to these and other challenges are as inept as they are insufficient. Even as waves of refugees from an exploding Middle East and North Africa triggered political and social crises across Europe, European diplomacy has remained essentially irrelevant in the region.

Europe has been passive in the face of Houthi interference with Red Sea commerce. Russia has kicked France out of Africa. Almost three years into Russia’s war in Ukraine, Europe still feeds Vladimir Putin’s war machine by buying Russian energy. Europe’s poorly conceived green policies have positioned China to destroy the automobile industry, a pillar of Europe’s economy and social stability.

As a result, Europe needs the U.S. more than ever but is less well situated to influence American policy—or to help the U.S. meet our many global challenges—than at any time in decades. This is why the leaders of once-great European powers tremble at every tweet from Mar-a-Lago and why Mr. Trump’s second term holds more challenges for Europe than his first.

For Europeans, the shift from Team Biden’s largely uncritical support will be painful. “Germany is my country’s closest and most important of allies,” President Biden told German Chancellor Olaf Scholz in October. For Team Biden, getting along with Germany was the foundation of smart foreign policy. That the Germans have been consistently and gravely wrong about Russia, China, Iran, climate, migration, the importance of strong defense and the condition of their own economy never seems to have registered with an American president whose worldview comes out of the 1970s and 1980s.

Under the circumstances, it’s easy to understand the schadenfreude with which much of MAGA World regards a weakened and demoralized Europe. The contempt with which Germany and the European establishment generally rejected President Trump’s correct and important criticisms of misguided European foreign and domestic policies still rankles.

But no matter how satisfying, settling scores isn’t how you make America great again. European decline isn’t good for the U.S. With the axis of revisionists on the prowl, Team Trump will need all the help it can get, and America’s goal must be to resuscitate Europe rather than to dance on its grave.

Europe has abdicated its role in history. The coming administration must work with partners like Japan that have the strategic clarity that so many Europeans lack. Countries like Israel, India, the United Arab Emirates and Saudi Arabia have read the signs of the times more accurately than our European friends. Argentina’s awakening from the fever dream of Peronism creates important opportunities in the Western Hemisphere. Indonesia, the Philippines, Vietnam and Thailand matter more than most European states to the future of American foreign policy.

Mr. Biden’s words to Mr. Scholz were sincere and heartfelt. But Europe is no longer the center of America’s foreign-policy universe, and barring a near-miraculous European recovery, future presidents will likely follow Mr. Trump’s lead in shaping their policies for the new post-Western world.