The love of liberty has nourished our nation since before its founding. Yet classical liberalism, which ought to provide common ground for left and right in the United States, is under attack today by prominent elements of both.

The discontents to which the vilifications of classical liberalism are a response are neither imaginary nor frivolous. But the vilifications obscure the means for reducing the discontents.

A number of well-known progressive politicians suppose that socialism provides the answers to the economic and social injustices with which they believe America is rife. They do not speak of “central planning” and “a command economy” — much less bandy about such terms as alienation, class struggle, and the proletariat’s eventual triumph over the bourgeoisie. But led by Sen. Bernie Sanders, who in 2016 made a decent run at wresting the Democratic presidential nomination from the establishment-anointed Hillary Clinton, and freshman Rep. Alexandria Ocasio-Cortez and her Green New Deal, the left has increasingly embraced socialist ideas. They want to direct the economy from Washington to correct the purported grievous misallocation of resources within the United States that stems, they believe, from the institutionalized privilege of white men. They also favor shifting authority from nations to international institutions to advance a global redistribution of wealth and power.

Meanwhile, noteworthy conservative intellectuals are keen to hitch their movement’s wagon to nationalism to combat what they perceive as the misrule of cosmopolitan elites who scorn local traditions and love of country. These conservatives generally shrug off nationalism’s long and stormy history; the variety of aspirations to which the planet’s diverse peoples have dedicated their collective lives; and the propensity to plunder, conquest, and empire frequently bound up with nations’ sense of their just deserts and appointed destiny. Paradoxically, nationalist conservatives downplay and sometimes despise the classically liberal traditions embodied in America’s founding documents, manners and morals, and political culture. Apparently misinformed about the flexibility that fortifies American constitutional government, they presume that tempering free trade, and opposing open borders and transnational government require the overthrow of classically liberal principles.

But is either socialism or nationalism an effective response to the challenges that confront liberal democracy in America? If taken seriously, do they require Americans to abandon liberal democracy? Or can the legitimate anxieties and objections of left and right be accommodated while remaining true to the principles of liberal democracy?

Thirty years ago this summer in The National Interest, a young State Department official set off a worldwide debate by arguing that the “unabashed victory of economic and political liberalism” in the practical realm encouraged the philosophical conclusion that liberal democracy was reasonable and just because it reflected the unchanging realities, and satisfied the essential requirements, of human nature. If the sensational claim at the heart of Francis Fukuyama’s “The End of History?” were correct, it would follow that all legitimate criticism of liberal democracy in America must be resolvable within the framework of liberal democracy.

With the Soviet Union, under the leadership of Mikhail Gorbachev, only the most prominent example of a wave of democratization sweeping the world in the 1970s and 1980s, observers of world affairs, Fukuyama wrote, “sense dimly that there is some larger process at work, a process that gives coherence and order to the daily headlines.” Notwithstanding the hedging question mark in his title, that larger process, Fukuyama indicated, was “the end of history as such: that is, the end point of mankind’s ideological evolution and the universalization of Western liberal democracy as the final form of human government.”

Fukuyama — three decades later the author of several important books of political analysis and a senior fellow at Stanford’s Freeman Spogli Institute for International Studies — could see perfectly well in the summer of 1989 that international conflict had not ended. And he did not suggest that soon all nations would be holding free and fair elections and protecting individual rights. Rather, he contended that “there are powerful reasons for believing that” liberalism in the large sense — the notion that human beings are by nature free and equal and that legitimate governments protect universal rights based on the consent of the governed — “is the ideal that will govern the material world in the long run.”

Drawing on the interpretation of Hegel and Marx developed by Alexandre Kojève in a legendary set of Paris lectures delivered in the 1930s, Fukuyama argued that while any particular state’s fidelity to the principles of liberal democracy could be improved, the principles themselves could not. The spectacular failures of liberal democracy’s chief 20th-century rivals, Fukuyama maintained, supported Kojève’s analysis.

Fascism seized on “the political weakness, materialism, anomie, and lack of community of the West as fundamental contradictions in liberal societies that could only be resolved by a strong state that forged a new ‘people’ on the basis of national exclusiveness.” But, Fukuyama writes, “Fascism was destroyed as a living ideology by World War II.”

Vastly more successful than fascism — and responsible for tens of millions of more deaths — communism insisted that capitalism could never overcome the class warfare between capital and labor. But everywhere it was tried, communism crushed freedom and immiserated the masses. Meanwhile, the protection of individual rights, the institutionalization of the rule of law, and the practice of democratic accountability enabled free societies to eliminate the worst excesses of unfettered capitalism, nourish equality, and promote general prosperity while greatly reducing grinding poverty.

The only other competitors to liberal democracy worth considering, argued Fukuyama, were religion and nationalism. “The rise of religious fundamentalism in recent years within the Christian, Jewish, and Muslim traditions,” he acknowledged, reflected “a broad unhappiness with the impersonality and spiritual vacuity of liberal consumerist societies.” However, notwithstanding the emergence of political Islam, he argued that theocracy lacked universal appeal.

Although a powerful force in world affairs, nationalism too lacked universal appeal, at least as a governing ideology. “The vast majority of the world’s nationalist movements do not have a political program beyond the negative desire of independence from some other group or people, and do not offer anything like a comprehensive agenda for socio-economic organization,” contended Fukuyama. In most cases, moreover, better representation within the framework of liberal democracy could satisfy nationalist demands.

Fukuyama concluded on a melancholy and aristocratic note. “The end of history will be a very sad time,” he wrote. “The struggle for recognition, the willingness to risk one's life for a purely abstract goal, the worldwide ideological struggle that called forth daring, courage, imagination, and idealism, will be replaced by economic calculation, the endless solving of technical problems, environmental concerns, and the satisfaction of sophisticated consumer demands. In the post-historical period, there will be neither art nor philosophy, just the perpetual caretaking of the museum of human history.”

The Berlin Wall fell just a few months after the publication of “The End of History?” The epic scenes of jubilant Germans from the East and West collaborating to dismantle the massive barricade that symbolized communist oppression — everyone knew the wall’s chief purpose was to keep East Germans in — heralded the complete collapse of communism in Eastern Europe. A little more than two years later, the Soviet Union dissolved itself. It appeared that world affairs were confirming Fukuyama’s thesis in real time.

But on Sept. 11, 2001, radical Islam brought America’s “holiday from history” — to recall Charles Krauthammer’s incisive phrase — to a fiery end. Since then, authoritarian regimes rooted in distinct national traditions — Russia, China, and the Islamic Republic of Iran, in particular — have asserted claims to exercise hegemony in their regions and beyond. Meanwhile, waves of left-wing radicalism and right-wing populism have shaken Western liberal democracies from within.

The resurgence of threats to liberal democracy — external and internal — does not refute Fukuyama’s principal thesis. The key claim was not that history guaranteed liberal democracy’s worldwide triumph but rather that concrete political developments had made manifest liberal democracy’s superior reasonableness and justness in comparison to all conceivable rivals.

The magnitude of the threats that have arisen over the last 30 years, however, does suggest that Fukuyama overlooked the resilience of authoritarian political alternatives. And that he underestimated the internal tensions and destabilizing passions inhering in liberal democracy — among them, on the one hand, the impatience with formal equality under the law that issues in a desire for an all-encompassing equality and, on the other, the quest for community and the longing for the sacred.

Reconciling these tensions has preoccupied lovers of liberty since before the nation’s founding. It will remain a task for friends of freedom in America and abroad.