Are we at a historical turning point in our world approach?

In economics, as in life, things often take longer to happen than you think they will and then happen faster than you thought they could. So it may turn out with the catastrophic international economic policies of President Donald Trump. It is possible that last week will be remembered as a hinge in history — a moment when the United States and the world started moving on a path away from the peace, prosperity and stability that have defined the past 75 years.

For all that has gone wrong in the past three-quarters of a century, this period has witnessed more human betterment than any time. The rate of fatalities in war has steadily declined,while growing integration has driven global growth and improvement in life expectancy and living standards. Progress is too slow, and not well enough shared, but Americans have never lived so well. This has been driven by remarkable developments in human thought, especially in science and technology, and a relatively stable global order that has been underwritten by the United States.

Will these trends continue? Optimists have suggested that despite the revanchist and often anti-rationalist rhetoric of his campaign, Trump has in the international sphere surrounded himself with rational establishment advisers and has either retreated or been stymied by Congress on proposals such as launching trade wars and building walls.

Until last week, they had a reasonable argument. No longer. We may have our first post-rational president. Trump has rejected the view of modern science on global climate change, embraced economic forecasts and trade theories outside the range of reputable opinion, and relied on the idea of alternative facts rather than evidence-based truth.

Even for conservative statesmen such as Ronald Reagan, George W. Bush and Henry Kissinger, the idea of a community of nations has been a commonplace. Come now H.R McMaster, national security adviser, and Gary Cohn, director of the National Economic Council, who have been held out as the president’s most rational, globally minded advisers. They have taken to the Wall Street Journal to proclaim that “the world is not a global community” and advanced a theory of international relations not unlike the one that animated the British and French at Versailles at the end of World War I. On this view, the objective of international negotiation is not to establish a stable, peaceful system or to seek cooperation or to advance universal values through compromise, they wrote, but to strike better deals in “an arena where nations, nongovernmental organizations, and businesses compete for advantage.”

In service of this theory, the president in the past two weeks renounced any claim to U.S. moral leadership by failing to convincingly reaffirm traditional U.S. security commitments to NATO and abandoning participation in the Paris global climate agreement. The latter is probably our most consequential error since the Iraq War and may well be felt even longer.

There will be consequences to all of this, as there were to the pursuit of short-term advantage rather than systemic stability at Versailles. One does not need to subscribe to pessimistic versions of Graham Allison’s “Thucydides Trap” as it relates to worries about how China as a rising power may fill the vacuum left by the United States. How, after the events of the past week, can U.S. adversaries and allies alike not follow German Chancellor Angela Merkel in concluding that the United States is now far less predictable and reliable? How can the responses be other than destabilizing?

It is essential that leaders in U.S. society signal clearly their disapproval of the course the administration is taking. History will judge poorly business leaders who retain positions on Trump administration advisory boards because they hope to be in a position to cut favorable deals. Elon Musk of Tesla and Robert Iger of Disney have taken the correct and principled stand by resigning their presidential appointments. More should follow.

What is to be done? The U.S. president is not America. The world will be watching to see whether Trump’s words and deeds represent an irrevocable turn in the nation’s approach to the world or a temporary aberration. The more that leading figures in U.S. society can signal their continuing commitment to reason, to common purpose with other nations, and to addressing global challenges, the more the damage can be contained. And, of course, Congress has a central role to play in preventing dangerous and destabilizing steps.