In a recent broadside against the Occupy movement, Alexander Cockburn assailed, among other things, “the enormous arrogance which prompted the Occupiers to claim that they were indeed the most important radical surge in living memory. Where was the knowledge of, let alone the respect for, the past?”

Cockburn may be prone to rhetorical excess, but it is striking how little the Occupy movement has identified with any particular tradition of American radicalism. At the height of the southern Civil Rights Movement, it was common in New Left circles to refer to the Freedom Riders as “the new abolitionists,” the title of a much-read 1964 book by Howard Zinn. No such cries of historical continuity were audible from Zuccotti Park.

If there is one political movement that has claimed kinship with an American revolutionary tradition these past few years, it has been the Tea Party, with its tricorn hats and its fetish for the Founders. The American Revolution, or at least its orderly, legalistic reputation, is no doubt congenial to the Right and often held up as proof of Americans’ imperviousness to radical adventures. Whatever the historical facts, 1776 is remembered as a mere “political,” and not a social, revolt: the solemn replacement of an imperial constitution with a republican one.

But the United States indisputably has a radical, indeed violent, social revolution in its past, one that expropriated, without compensation, almost one quarter of the productive wealth in the country and by the same act liberated four million human beings from bondage. That, of course, was the Civil War and Emancipation. And its political agents were Abraham Lincoln and the Republican Party.

This last observation would have once been considered unremarkable. But as James Oakes recounts in these pages, it has been submerged in recent decades by a new historical orthodoxy that attempts to sever the link between the Republican program and emancipation, portraying the latter as an accidental byproduct of the former.

In response, Oakes demonstrates that Republicans took power in March 1861 with a comprehensive antislavery policy of which emancipation was both the actual and the intended outcome. However unplanned their specific course, the Republicans were revolutionaries.

That is why, to quote the words that Marx’s International addressed to Lincoln in 1864, the proletarian radicals of Europe “felt instinctively that the star-spangled banner carried the destiny of their class.” Robin Blackburn details this transatlantic affinity in his essay on Marx’s milieu during the Civil War era. Indeed, during the war, Radical Republicans in Congress were commonly cursed as “Jacobins,” and their unofficial leader, Thaddeus Stevens — soon to be buried in an interracial cemetery — was nominated by one British observer “the Robespierre, Danton, and Marat of America, all rolled into one.”

It is worth asking, then, why the American left has lately neglected this revolutionary inheritance.

In the American system, no political party can durably exist without the ability to win at least half the vote in a meaningful number of elections, yet almost by definition, no truly radical program can ever quickly gain such broad assent.

In the mid nineteenth century, a faction of abolitionists understood this dilemma. Figures such as Charles Sumner, Salmon P. Chase, Joshua Giddings, and John P. Hale, rejecting the heavily prefigurative and antipolitical style of activism practiced by William Lloyd Garrison and his followers, saw that a strategic approach to abolition was required, one in which the “cause of the slave” would be harnessed to a wider set of appeals.

At each stage of their project, from the Liberty Party to the Free Soil Party and finally the Republican Party, progressively broader coalitions were formed around an emerging ideology of free labor that merged antislavery principles with the economic interests of ordinary Northern whites.

The outer layers of these coalitions attracted voters and politicians who lacked the hard abolitionist principles of the militants, and in a racist society it was inevitable that many of the converts to Free Soil would vaunt theirs as the “true white man’s party.”

But the original nucleus of radicals — despite their own time-bound attitudes — lent the project an inner egalitarian spirit, visible in party campaigns for black suffrage and civil rights across the North. And when the moment of mass radicalization finally arrived in the wake of the Kansas-Nebraska Act, these abolitionists stood triumphantly at the heart of the networks that became the new Republican Party. “Our position is now rather enviable,” wrote Giddings in 1854. “We lead the hosts of freedom.”

Today on the radical left, there is a widespread allergy to political strategy as such. There is far more communion with the countercultural legacy of Garrison than with the political acumen of Frederick Douglass, who by 1852 had become secretary of the Free Soil Party, commenting that “what is morally right is not at all times politically possible.”

The Second American Revolution was tragically cut short, its unfinished work still visible on our streets and in our prisons. That’s all the more reason to embrace the legacy of its most far-sighted champions.