Donald Trump is the first President since at least Teddy Roosevelt to reject the idea of international cooperation. The presidents of the 1920s—Warren Harding, Calvin Coolidge, and Herbert Hoover—are often remembered as isolationists. But while they refused to enter the United States into security pacts with European nations, all three of those presidents involved America in various international efforts to dampen global conflict, from disarmament agreements to treaties outlawing war. Beginning with Franklin Roosevelt, all presidents since World War II have gone further still, tying the United States to collective security arrangements throughout Asia and Europe.

The basic assumption inherent to international cooperation is that agreements between countries can be mutually beneficial. It is an assumption directly at odds with Trump’s zero-sum thinking. Whether because he is a genuine sociopath or because his worldview was formed in the unforgiving Manhattan real-estate industry, Trump is incapable of understanding that multiple parties can benefit from a shared transaction. For Trump, there is only one winner in any relationship; the rest are losers. Applied to international affairs, that means America can only win—and win it must—when other countries lose. (The exception to this rule is Russia, where Trump personally benefits from cooperation, overriding any concerns about the fate of America.) And the way to win is through unilateralism, confrontation, or aggression, depending on the situation.

This mindset is antithetical to the thinking outlined in political scientist Tony Smith’s new book. Why Wilson Matters is an attempt to rescue liberal internationalism from both realist critics who deride it as a dangerously naïve perspective and from foreign-policy hawks who selectively borrow from the Wilsonian tradition, injuring it in the process. Smith’s book also offers a revised U.S. strategy for international affairs. Under a President Hillary Clinton, it could have provided a thoughtful blueprint for American strategy. But under Trump, its recommendations are obsolete. Call it Wilsonianism or call it liberal internationalism, the bipartisan foreign policy that lasted mostly intact from FDR to Barack Obama is dead, and it is not likely coming back.

What was Wilsonianism? Smith answers this question by looking beyond the Wilson presidency, from 1913 to 1921, to the writings he produced throughout his life. The most important contribution of Why Wilson Matters is how Smith connects the ideas of Wilson the thinker with the actions and speeches of Wilson the President. Before he was New Jersey governor for two years, Wilson was a professor of politics; he taught at, and eventually became the president of, Princeton University. He was regarded as among the foremost political thinkers of his time, and he is the closest thing we have gotten to a philosopher-king. Wilson’s terrible ideas and policies on race—even for his time, his contempt for African-Americans was pronounced—shouldn’t obscure his brilliance in many other areas.

Smith does not dwell on Wilson’s best-regarded book, Congressional Government, however, because of its focus on domestic policy. Instead, Smith looks to Wilson’s other, lesser-known writings to uncover the sources of Wilsonianism: books like The State and Constitutional Government, and lectures he gave as a professor. A few of Wilson’s trademark ideas—the superiority of democracy as a political system, for instance—were developed long before he took high office. In a 1901 essay, he wrote, “The consent of the governed must at every turn check and determine the action of those who make and execute the laws.” That notion was the genesis of Wilson’s insistence during and after World War I that a lasting peace would be secured only by countries acting with their citizens’ consent.

In addition to his writings, Wilson’s various remarks as President over eight years showed a remarkable capacity to learn and evolve while in office. He proved himself able to fashion his own almost entirely original, near-coherent foreign-policy approach despite having limited experience in foreign affairs before becoming President. On this, nobody has systematized Wilson’s thought as well as Smith, not even top Wilson scholars like Arthur Link and John Milton Cooper Jr. Smith concedes that he might be projecting a clarity onto the President’s foreign-policy approach that it probably didn’t possess. Given that Wilson became an invalid while still a sitting President and was never able to outline his views in any detail beyond his speeches, we can’t be sure exactly to what extent he would endorse what has become known as Wilsonianism. (Marx’s famous line that, “If anything is certain, it is that I am not a Marxist” is instructive here.) Nonetheless, Why Wilson Matters offers a persuasive case that liberal internationalism as a coherent body of thought can be traced back to Wilson’s writings and actions. At a time when conservative intellectuals are finding their foreign-policy traditions destroyed by President Trump, it is crucial that liberals understand our own origins.

According to Smith, the “ism” in Wilsonianism is comprised of four interrelated but distinct prescriptive ideas for how America should approach the world: foster cooperation among democratic governments; further economic integration; encourage multilateral institutions that enhance international law, free markets, and mutual defense; and ensure that the United States leads a peaceful community of nations. “[T]he promise of this unity is mutual defense and peace, which no aspect alone can be expected convincingly to deliver, but whose possible establishment, thanks to the interaction of these various developments, is the prime tenet of liberalism’s secular faith,” Smith writes. But in its American context at least, Wilsonianism is indistinct from liberal internationalism, though the latter was endorsed by Václav Havel, Mikhail Gorbachev, and Nelson Mandela.

To some degree, though, it should be acknowledged that Wilsonianism also has its genesis in the American Revolution. Inherent to the ideals of the Founders was a messianic belief that mankind could be redeemed by nations ruled by equal citizens. But alongside that belief was a concern that interacting with the world would be corrupting. As Smith nicely puts it, Wilson’s “achievement was to give to American nationalism an international vocation.”

How did he accomplish this?

Wilson had long been a teacher, and during his second term, before he suffered the stroke that would incapacitate him, he essentially tried to teach Americans the ways of liberal internationalism. Yet, they were not completely unschooled in global affairs. The Spanish-American War of 1898, waged by President William McKinley, led the United States to fight beyond its borders for the first time and take possession of far-flung territories. Despite the war’s significance in bringing the country to the level of one of the world’s great powers, America’s military engagement abroad was temporary and unilateral. This reflected Vice President Theodore Roosevelt’s perspective as much as it did McKinley’s.

Roosevelt was Wilson’s foreign-policy opposite. They outlined dual approaches to the world: Roosevelt advocated military force, imperialism, and unilateralism; Wilson called for diplomacy, self-determination, and multilateralism. Perhaps Roosevelt’s approach was too ruthless for Americans, conditioned as they were to seeing their country as having a moral mission in the world. Or perhaps he was too ahead of his time, proposing a high degree of involvement in world affairs before Americans were truly ready for it. Whatever the reason, it was Wilson’s vision that dominated American foreign policy in the second half of the twentieth century. Even the often coldblooded President Richard Nixon recognized that he operated partly in the Wilsonian tradition, insisting on using the professor’s desk in the Oval Office. There were instances of America operating with Roosevelt’s Big Stick—from Vietnam to the Dominican Republic—but on the big questions of collective security and multilateralism, Wilsonian ideas won out. Even before the assassination of Archduke Franz Ferdinand lit the fuse that led to World War I, Wilson was educating his fellow Americans on the need for a liberal internationalist foreign policy. In October 1913, he told business leaders that interests divide nations but that “sympathy and understanding does unite them.” He wanted to see “the development of constitutional liberty in the world. Human rights, national integrity, and opportunity as against material interests.” These were noble words, and they laid the groundwork for Wilson’s teachings to come.

Wilson had been elected in 1912 on a platform of non-intervention in European affairs, consistent with every President preceding him save Roosevelt. He ran as a progressive, and he was committed to reforming domestic policy largely along progressive lines (and succeeded in doing so to a remarkable degree in his first term). As late as 1916, he won reelection with the slogan “he kept us out of the war.” Roosevelt was salivating at the thought of America’s involvement in the war, but Wilson initially resisted the impulse to intervene.

The war did, however, inspire Wilson’s brilliant reflection on its causes. As outlined best in The Folly of Empire, a book by the journalist John Judis, Wilson attributed the cataclysmic war to numerous factors: the reliance on a balance of power to keep peace in Europe rather than nations acting in concert; rivalry over colonies; commercial competition; “might makes right”; and autocracy’s inherent aggressiveness. “He saw German aggression as the immediate cause of the war—and from the start privately favored an Allied victory—but he also believed that the war was rooted in a fractious international system, which, if not changed, would give rise to future wars,” observes Judis. Although it can seem that the world is collapsing, the post-WWII era is actually defined by the absence of war between great powers and the forward march of global democracy. Trump’s destruction of the liberal world order threatens to undo all that has been accomplished since Wilson fashioned his theories.

What is striking is how organically the tenets of liberal internationalism emerged from Wilson’s analysis of the war. The alternative to the balance of power was multilateralism; to imperialist races, national self-determination and sovereignty; to commercial competition, economic integration; to social Darwinism, the equality of all nations; and to autocracy, democracy. Wilsonianism arose not out of any abstract theory—indeed, Wilson revered Edmund Burke above all other thinkers—but as a set of practical ideas responding to specific dangers evident in the world.

Wilson understood that technologies, from radio to submarines, were collapsing distances, rendering America’s geographical isolation from Eurasia inadequate as a defense. Soon after the war commenced, Wilson wrote to his brother that “modern conditions had brought the world into such a close neighborhood that never again would it be possible for the world at large to regard a quarrel between two nations as a particular and private quarrel, but that an attack in any quarter was an attack on the equilibrium of the world.” Even if something of an overstatement, Wilson’s astute assessment of a shrinking globe was common to U.S. policymakers 30 years later, but rare in his time. It would be the underlying assumption for American foreign policy from 1941-2016. But now something has changed. Now, the belief that America can isolate itself from the world is here again. The belief that border walls and refugee bans can create a Fortress America solid enough to withstand penetration from terrorism, an ascending China, and globalization. This perspective was supposed to have been killed when the bombs rained down on Pearl Harbor, but it has been resurrected by Trump.

A professor at Tufts University, Smith is the rare writer who has been right about most foreign-policy issues of the past quarter-century. He is best-known for America’s Mission, the definitive history of the country’s efforts to promote democracy abroad. Released in 1994, it reflects the optimistic spirit of liberal internationalism that reigned between the Cold War’s end and the 9/11 attacks. America’s Mission “endorses liberal democratic internationalism by insisting on the tremendous benefits that accrued to the United States from the restructuring of Germany and Japan after 1945 into democratic states…[and] the expansion of democracy today in Eastern Europe (including Russia), Latin America (especially Mexico), and parts of the Far East.”

And yet, while America’s Mission showed pride in the accomplishments of liberal internationalism, it was still cautious. Smith writes, as well: “Liberal democratic internationalists should understand that democracy cannot be foisted upon a world that is unready for it.”

Around that same time, Smith wrote an article in Foreign Affairs defending President Bill Clinton’s intervention in Haiti. He called for Clinton to define a new post-Cold War era by using force against massive human rights abuses. But even then, he wrote that U.S. democracy promotion was unsuitable in Africa, China, and most of the Muslim world. He conceded that America needed to cooperate with countries with different political systems and recognize the limits to its power.

Years later, Smith began worrying, though, that liberal internationalism was morphing into liberal imperialism. His 2007 book, Pact With the Devil, argued that liberals had provided the intellectual underpinnings for George W. Bush’s invasion of Iraq. The book was relentlessly damning, written with the rage and finger-pointing that defined Bush-era liberalism. “Neoliberals were the functional equivalent for the Democrats of the neoconservatives within the Republican Party, a pro-war faction able to articulate in seemingly persuasive fashion why America’s moment of unrivalled power meant embracing a mission that would echo through the ages for its vision and its courage,” Smith wrote. For all its overheated rhetoric, Pact With the Devil is still the best work to understand how many liberals and Democrats—think of writers like Paul Berman and politicians like Joe Lieberman—injected Wilsonianism with steroids and became Bush’s enablers.

Pact With the Devil was motivated by a sort of ideological self-examination. “When I arrive at the Pearly Gates, the question from Saint Power I most fear will be how, given the evidence from the war in Iraq, I myself could ever have been so naïve as to have put so much intellectual stock into supporting Liberal Democratic Internationalism,” were the book’s opening lines. That examination led him to an investigation into Wilsonianism, which he believed liberals and neoconservatives had misunderstood in applying it to Iraq.

Bush adopted the rhetorical mantle of a central aspect of Wilsonianism: democracy promotion. He made a few glances in that direction before the invasion of Iraq, but it was really only after it became clear that weapons of mass destruction were not going to be found that he began claiming that promoting democracy was the major impetus of his foreign policy. His second inaugural address was, unsurprisingly, a soaring valentine to the universal value of democracy.

A debate soon sprouted up over whether Bush was, therefore, truly Wilson’s heir. Scholars like David Kennedy and John Lewis Gaddis situated Bush firmly in the Wilsonian tradition. Conversely, in an edited volume to which Smith contributed, The Crisis of American Foreign Policy, G. John Ikenberry and Anne-Marie Slaughter defended Wilson from Bush’s bastardization, claiming that Wilson was a deep believer in multilateralism, something Bush clearly scorned.

Why Wilson Matters is the full account of Smith’s thinking on where liberal internationalism went wrong. He identifies three stages of Wilsonianism. The first stage, “classical Wilsonianism,” was that fashioned by the man himself. The second stage, “hegemonic Wilsonianism,” was the Cold War foreign policy the United States carried out. And the third stage, “neo-imperialist Wilsonianism,” began with the Cold War’s demise and carries through to the present day. Smith thinks that the Bush-Obama years were largely indistinguishable and characterized by hubristic failure. “The tragedy of American liberal internationalism by late 2011 was that a framework for policy that had done so much to establish America’s preeminence in world affairs between 1945 and 2001 should have contributed so significantly to its decline thereafter,” he writes. He argues that when Marxism-Leninism died, liberal imperialism absorbed its intoxication with understanding history’s direction and being able to encourage it.

Smith’s analysis overstates the continuity between the Bush and Obama eras, though. In Iran, Egypt, Russia, Libya, and certainly Syria, Obama was far from committed to promoting democracy. Indeed, he was routinely criticized by liberal hawks and conservatives as being insufficiently militant about intervening to support good government. Similarly, while Bush seized upon democracy promotion as a rationale for his invasion of Iraq, Smith is weirdly credulous about this claim. There is no evidence that Vice President Dick Cheney or Defense Secretary Donald Rumsfeld, the two men who encouraged Bush hardest to invade Iraq in 2002, ever cared about inspiring democracy. Instead, they were obsessed with demonstrating American strength and credibility.

For all Smith’s concern about over-application of Wilsonianism, Why Wilson Matters is also being released at an unfortunate time. “My hope has above all been to reinvigorate a tradition in United States foreign policy that has been impoverished by those who would turn it to purposes for which it originally was neither even dimly intended nor at all appropriate,” he writes. Wilsonianism, the book continues, is in crisis because it doesn’t properly understand its history, and because it has been misused by neo-imperialists. Under a Hillary Clinton presidency, such concerns would be urgent. But under a Trump presidency, they are obsolete.

Liberal internationalism is indeed in crisis—much greater crisis than Why Wilsons Matter understands. But its fragility is not a result of its adherents’ ideological amnesia or even its distorted association with failed policies like the Iraq War. The decline of Wilsonianism has broader roots in shifts in American society.

These shifts were best illuminated by a brilliant 2007 article by political scientists Charles Kupchan and Peter Trubowitz.“Dead Center,” as it was titled, provided data showing that the bipartisan consensus that lasted throughout the Cold War in favor of liberal internationalism is gone.

Kupchan and Trubowitz located the sources of liberal internationalism’s demise in two factors. The first is the removal of any peer competitor to the United States in the global arena. The threats of imperial Japan, Nazi Germany, and the Soviet Union were so overwhelming and obvious that they concentrated most Americans’ minds in the same direction. Once those regimes were defeated, a vacuum in the purposes of American foreign policy opened up. That vacuum led to a split between Democrats and Republicans—and indeed within the parties, as well—on the nature of U.S. engagement with the world.

The other factor that has wounded liberal internationalism is the emergence of a level of domestic polarization unseen since the Civil War era. Given that liberals and conservatives have sorted themselves into different parties, and indeed often into different neighborhoods and entire cities, it is only to be expected that their divisions over America’s approach to the world would inevitably become extreme, too.

The terrorist attacks of 9/11 temporarily reassembled the bipartisan consensus on foreign affairs. George W. Bush was not a fan of international organizations, but he had a commitment to keeping America as the underwriter of security in Europe and Asia. Barack Obama had an underappreciated degree of support in Congress for his foreign policy, with several important exceptions, such as enforcing the “red line” he charged Syrian leader Bashar al-Assad with crossing should he make use of chemical weapons.

But there is no consensus on fighting terrorism, which is an asymmetrical threat that doesn’t lend itself to easy military responses. Remarkably, Kupchan and Trubowitz wrote that “historical precedents also suggest that the threat of Islamic extremism may over time lead Americans to raise protective barriers at home, rather than to project military power abroad or reinforce multilateral institutions.” That, of course, is exactly what has happened with the rise of Donald Trump.

Trump has singlehandedly exploded the post-Pearl Harbor belief, universal among all presidents and even all major party nominees, that American security is best guaranteed by its fellow democratic nations. He has expressed admiration for the leaders of Russia and China, the two autocratic challengers to liberal democracy. He admires their leaders for being “tough,” a view consistent with his routine equation of cruelty and strength. Trump’s repeated declarations that America should have taken Iraqi oil is a violent form of imperialism with which even Teddy Roosevelt would not have been comfortable. Our new President’s verbal assaults on long-standing alliances—in NATO and with South Korea and Japan, among others—amount to a radical overhaul of American foreign policy.

Aside from the hideousness of Trump’s views, they are diametrically opposed to anything resembling Wilsonianism. Perhaps Americans elected a man possessed of a worldview so antithetical to liberal internationalism as almost a mistake, given that foreign policy did not seem to factor into many voters’ considerations. More likely, however, the era of Wilsonianism has passed, and future generations will have to find new ways to grope with global challenges. Wilson would understand the difficulty.