Scope and Content Notes:
SDS began as the student affiliate of the League for Industrial Democracy (LID), an organization of Fabian minded Socialist intellectuals and labor union officials that published detailed policy statements on public issues from a Social Democratic point of view. The LID sponsored a Student League for Industrial Democracy (SLID) that had substantial membership at several colleges and universities in the Debs era, but by the late 1950s both the parent organization and the student wing had declined to tiny remnants. However, the student wing had picked up energetic organizers influenced by the emerging New Left. In 1960 they rename the organization Students for a Democratic Society, suggesting how they had been influenced by such New Left oriented thinkers as C. Wright Mills. Mills criticized what he called the “labor metaphysic” of the Old Left and urged young activists to pursue new ideas and new strategies. This began a process of estrangement from the parent organization over such issues as anti-communism and the Vietnam War. The ILD was militantly anti-Communist and supported U.S. policy in Vietnam. Most SDS members had scorn for Communism (at least of the capital "C" variety; some of them could reasonably be called small "c" communists), but they were anti-anti-Communist because they considered American anti-Communism as a paranoid crusade stifling creative thinking in the United States. SDS vigorously opposed U.S. policy in Vietnam. SDS did not formally break with the LID until 1965, but the mutual antagonism between the LID and SDS was quite evident several years before.
In its early years SDS was a tiny organization with only a few hundred members on a couple of dozen campuses. It was far smaller than the Student Peace Union, and indeed smaller than the youth organizations of Old Left parties like the CP and the SWP. But the organization began to attract attention after the publication of its Port Huron Statement in 1962 in which it criticized both sides in the Cold War, discussed how both failed to satisfy unfulfilled utopian longings, and advocated as its alternative what it called participatory democracy. SDS also attracted new members through its early collaboration with the Student Non-Violent Coordinating Committee (SNCC) and its early opposition against the War in Vietnam. It expanded rapidly after its sponsorship of the first large demonstration against the War in Vietnam in April 1965.
By its final years SDS was the largest, indeed the only substantial, organization of the American New Left. How large is impossible to say, in part because SDS, as part of its ideology eschewed the formal bureaucratic apparatus of Old Left organizations. In theory you became a member of SDS by filling out a membership application with a small application fee and mailing it off to the national office in Chicago. In return you received a membership card and a subscription to the national organization’s newspaper, New Left Notes. But most people who considered themselves members of SDS never bothered to do that. Local chapters of SDS operated as wholly autonomous units. In practice an individual was a member of the local chapter if they showed up for meetings and participated in group events. No one had to show a membership card to vote in meetings. De facto membership fluctuated wildly. But by the end of the 1960s certainly several hundred thousand people had participated in events organized by SDS.
In its final years SDS was sharply divided by internal factions. One faction, affiliated with the Progressive Labor Party (PLP), advocated a strategy of a worker-student alliance, and hoped to steer SDS in an Old Left direction. They captured the remnants of the organization after the 1969 convention in which the factions split apart. A second group, harboring romantic fantasies of domestic armed insurrection, conceived of itself as the Americong (in the words of a Jefferson Starship song). They became the Weathermen who attracted considerable press attention despite numbers that never exceeded two or three hundred. A third faction, essentially defined only by its opposition to the other two, had even less staying power. Within a year of the 1969 convention none of the factions amounted to anything. Most of the membership drifted away from all of them in bewilderment.
This sad ending reflected a broader sense of strategic impasse among New Left activists. The antiwar movement staged many of the largest political demonstrations in American history, but the war raged on. Activists talked about participatory democracy and shouted “Power to the People!” but they were painfully aware that the larger public viewed student activists with hostility even as public opinion about the war was shifting. Factional conflict within radical movements was also stimulated by the penetration of the national security state into the movement. Political authorities were sufficiently worried by the revolutionary posturing of New Leftists and Black revolutionaries that they assigned thousands of agents to monitor and infiltrate activist groups. As part of the Federal government’s Cointelpro program, undercover agents were instructed to encourage internal conflict and factional division.