In a knife-edge election, many are the causes that tip the balance between victory and defeat. Politics is, as Branch Rickey memorably said of baseball, “a game of inches.” Minor changes in a campaign scenario produce major differences. Surely Donald Trump’s victory derived in no small part from his appeal — his persona, his claims, his tone, his targets. He got a boost from television, which found him a magnet for eyeballs and eardrums. He took shrewd advantage of Hillary Clinton’s weaknesses and errors. In no small way his appeal was boosted by Republican vote suppressors, by James Comey’s astonishing last-hour insinuation, and by the dynamic duo of Vladimir Putin and Julian Assange, whose day-by-day leaks of Democratic National Committee emails furthered the association between the Clinton campaign and unfathomable corruptions. For Trump to win — that is, to win the Electoral College — every one of ten or fifteen factors had to go his way. They did.

But obviously, to understand Trump’s triumph, we need to plunge deeper, for what he is and what he represents are scarcely unique. Indeed, his movement would still have been dangerous even if some 75,000 votes had gone differently in Pennsylvania, Michigan, and Wisconsin. The affinities between his flabbergasting victory and the Brexit campaign — along with nativist movements in France, Holland, Germany, and elsewhere in Europe — are obvious. As Trump would say, something’s going on.

All unhappy times are unhappy in their own ways, but the emergency upon us today belongs to a longer-running and wider-ranging story. Trump and his equivalents elsewere take advantage of the feebleness of a left whose institutions are lifeless and that has become severed from popular longings.

Here is the backstory. The upsurge of authoritarian, nativist leadership throughout the West is yet one more episode in a long-running clash between two visions, or spirits. One is universalist, the other tribalist. One emphasizes the commonality of the human condition, the other, fundamental differences. They embody distinct answers, emotional, cultural, and intellectual, to these definitive questions: (1) What, or whom, do I belong to; and (2), Who are my enemies? The answers gaining ground are: (1) my tribe; and (2) other tribes.

Call the two visions by contrasting images: the commons and the wall. The commons lives on a vision of inclusion; the world of walls, on exclusion. The commons’ prime emotional base is solidarity; in the world of walls, the prime tone is resentment. The political form of the commons is democracy; the world of walls craves autocracy to build and police the walls.

The commons is not a final achievement, but an evolving project — an “uncompleted project,” as Jurgen Habermas said of modernity — for de facto exclusions, suppressions, and immoral hierarchies persist even in times and places when universalist rhetoric rides high. But the commons as a vision has a self-fulfilling dynamic. Affirming the commons is typically a lever that makes rights expand to become more universal even if no certain endpoint can ever be reached. (No one has made the point more trenchantly than Frederick Douglass in his 1852 address, “What, to the Slave, Is the Fourth of July?”) The commons is typically the goal of what has been called, since the French Revolution, the Left. I am not speaking of parties, but of spirits, though there is at times an overlap. The building of walls is usually the work of the Right, but this demarcation is not exclusive. The important point is that walls appeal most when the commons is fragile, and the strength of each thrives on — and reinforces — the weakness of the other. Today’s plain truth is that in so much of the so-called advanced world, the commons does not inspire as strong an attachment as walls.

The dialectic of universalism and tribalism stems from the Enlightenment, whose first expression was liberal and individualist. Thomas Jefferson, among others, translated John Locke and the Scottish Enlightenment theorists into a working politics that took power in the name of anti-imperialism. The liberal thread continued throughout the 19th century. Its chief avatars were John Stuart Mill (not especially anti-imperialist) and Alexis de Tocqueville, who, whatever his ambivalence about the American experiment, was inspired by the notion that democracy was the wave of the future.

Liberal universalism, with a democratic bent, inspired movements that swept across Europe, cresting in 1848: they were both liberal and nationalist. Their nationalism was an assault on imperial rule, and the respective revolutionaries (German, Austro-Hungarian, Italian) felt allied; there were, at least, elective affinities. Most of these movements failed, though they were inspirational. If liberalism and nationalism were ultimately contradictory, this was not their problem.

From 1848 onward, for more than a century, the other politics of the commons was socialism, which was fundamentally globalist. 1848 was not only the year of Europe’s national risings, but also the year of the Communist Manifesto, which propounded the notion that the economic revolution of capitalism was, willy-nilly, unifying the world by creating a universal class, the “international working class,” which would ultimately, in the words of The Internationale, “be the human race.”

The dominion of socialist ideas can be approximately divided in two. In Phase I, the Social Democratic idea spread across Europe, only to crumble in 1914 as the German Social Democrats voted war credits to the Kaiser so that Germany could kill French workers. The wreckage of nineteenth century socialism left the decisive initiative to the Bolsheviks, who took command of Phase II. Bolshevism was a disaster from the start, crushing democracy and human rights, though only in 1956, with Khrushchev’s speech on Stalin and the Soviet invasion of Hungary, were the eyes of many true believers opened.

After World War II came varied attempts to revive the politics of the commons. Postwar Social Democracy, in one form or another, reigned in Western Europe for several decades until immigration and financial disaster overcame it. With inequality growing and economies failing, the caste privileges of political and cultural elites came to seem illegitimate. The haplessness of the European Union speaks for itself.

Meanwhile, Maoism and other varieties of Third Worldism rewrote the Marxist idea of a global proletariat destined to prevail into an anti-colonial mystique, but theirs was a false start, with tyranny as its common destination. The global New Left of the 1960s revolted against authority in the name of participatory democracy, and against liberal globalism as a cover for imperialism. But participatory democracy was most appealing to minorities — the highly educated and the dispossessed. The revolt against authority could not provide a template for governance in a world of gargantuan institutions. And opposition to imperialism could not generate a common vision, nor could it cope with waves of violence generated by a new pretender to globalism — the warriors of the Islamist caliphate, themselves the proponents of a universal belief to be imposed by the sword.

Under pressure from many quarters, the social democratic ideal lost its tensile strength. It no longer aroused passion. In the United States, its prime institutions, labor unions, were vanquished by savage capitalism. A diminished version of cosmopolitanism, the universal attachment that was the pride of socialists, now thrives under capitalist sway, especially in the urban domains of professional classes dependent upon the prosperity that refurbished capital has delivered. The prime movers of globalism are headquartered on Wall Street, in the City of London and Davos. Against them, social and environmental movements crop up and fight, often in the name of universal values, but the emotions they mobilize, however fierce, do not coalesce into a political form that might conceivably govern.

As for the liberal nationalism of the nineteenth century, it devolved into the demand for self-determination. Under globalist pressures, liberal nationalism drifted away from democracy and toward tribalism, or what Fareed Zakaria has called “illiberal democracy.” Tribalism is the new zeitgeist. Its leading instrument is the trumpet. Passions build walls, celebrate them, and mobilize to defend them. The commons sounds bland and boring in comparison. Social Democracy does not inspire. For all the clamors of social movements mobilized against the global brutalities, there is no new “Internationale.” Strikingly, what we witness today is the particular pathos of secular universalism. The prime exponent of human commonality today is the Pope.

Is the commons doomed? Not necessarily, although its immediate future is bleak. History has not ended. The tribalist zeitgeist has its crests and troughs. To satisfy the longings that bring tribalists to power is no cakewalk. But it would be silly to think that once America’s High Priest of Tribalism returns once and for all to his gilded marble palace on Fifth Avenue for endless rounds of golf and deals, tribalism will surrender. There will be no Appomattox moment. Messaging miracles, and wishful thinking will not suffice. Universalists will have to insist that nation-states be rooted in civil values, open to human differences and sensitive to human rights. They must be justified by universalist arguments, not exclusive tribalisms of race or religion. There is obviously much more to be said about the requirements of such nation-states, but one point is clear: To defeat the rhapsodists of the wall, devotees of the commons will not only have to work as hard and energetically as the tribalists. They will have to hear, compose and play new music.