Dan Berger argues the need to move "beyond the blame game" but he does consider two competing claims: the PL faction was to blame or the RYM I/Weather was to blame.
"PL was, in fact a formidable force in the dissolution of SDS. Jared Isralie, a PL leader with a major presence in SDS, has said that if anyone was to blame for the organization's death, it was PL... Although PL had its strengths -- emphasizing ... that class was an important subject and that activists needed to prioritized political study -- the group's politics and culture became increasingly contradictory to the direction in which much of SDS was moving. To blame the organization *completely( for SDS's downfall, however, misses some of the nuances of the period. Many chapters had little or no contact with the small Communist sect, reflecting the increasing disconnect between SDS as a national organization, whose leaders had constant battles with PL, and the various local chapters of the group -- many of whom, especially in the South or the Midwest, had little relationship with the Maoist group. With its rigid style and dogmatic approach, PL surely contributed to the polarization in SDS -- but it was not the only polarizing force, nor was polarization the sole factor in the downfall of the organization.
More common than charging PL is blaming Weatherman for the dissolution of SDS. Leading the charge in this regard is former SDSer turned professor and self-styled Sixties expert Todd Gitlin. In the documentary 'The Weather Underground," Gitlen accuses Weatherman of "organizational priracy," because it "ran off with" and killed the student movement. While Gitlin is excessive with his anti-Weather vitriol, he is not alone in suggesting that the group was responsible for the death of SDS. Other, more progressive, historians criticize Weatherman for going underground at a time when -- as George Katsaificas puts it in his excellent book _The Imagination of the New Left -- the mass movement was looking for leadership.
But is it productive or necessary to place blame? It is unlikely that SDS as an organization could have continued in the same manner for much longer. It was 100,000 people ,most of them young and inexperienced, taking on, in David Gilbert's words, "the most powerful government in world history." Internal contradictions, rapidly changing world conditions, and increased government repression tore apart other famous groups of the time, including SNCC in the late 1960s and the Black Panthers in the early 1970s. Though the two Black militant organization were under much more pressure from the state, the point is that this was a time period marked by rapid change, and is naive to blame the end of an entire movement -- much less an entire time period -- on the dissolution of SDS, let alone to blame the death of SDS on one faction within it. Across the globe, splits with Maoist , Trotskyist, and democratic-socialist factions were endemic. They reflect divergent political perspectives and worldviews, not just brutal factionalism. ...
It seems that, regardless of the sectarianism of PL or the arrogance of Weatherman (or the vanguardism of RYM II), SDS lacked the structure and strategy to continue amidst all that was going on as the 1960s drew to a close. While united around opposition to the war and to racism, SDS chapters in places like NYC, Madison, Chicaog, and San Francisco were in a very different place politically from those in Charlotte, Duluth, Des Moines, and other small cities with less of an activist infrastructure or lacking direct connection to the Black movement and other struggles by people of color. Heightened repression, coupled with the turn to revolutionary analysis, led many to become enamored of Leninism. The result, as evidenced in the fracture of RYM, was a move toward building vanguard Communist parties or an armed movement, both ultimately relying on small, cadre-based groups rather than mass organization.
Others left SDS to build "back-to-the-land" communities or pursue spiritual enlightenment. Many continued working in anti-racist and antiwar groups as evidenced by the massive flowering of activism following the Cambodian invasions and the killings at Kent State. And more than a few left SDS to build the emerging movements for women's and gay liberation. ...
SDS, however, did die, It was fatally wounded in the summer of 1969, and died in the winter of that year, as WEatherman/SDS began to dismantle the national infrastructure and build what David Gilbert calls "an unprecedented, if seriously flawed group that carried out six years of armed actions in solidarity with national liberation struggles." In June '69, though, those who had assumed control of SDS weren't quite sure what direction they would go in -- or at least, how far they would go. But they were excited, eve optimistic about what lay ahead. The Weatherman faction left the convention with a specific organizing task in mind -- to galvanize white working class youth in battle against the state, though community organizing projects that summer and through a mass action that fall."
I will try to find time to write more about the elitist "fight the people" argument that came out of Weather right after this time. Basically, they said what some folks on this list often say: fuck the people. something needs to be done to wake them from their stupor. if we are shocking enough, it will force the retrogrades to reveal themselves and we won't have to bother dicking with them in the mean time.
To Weather, it was considered a way of rooting out unrepentant racists and only working with the people who came to realize that racism and imperialist domination had to be dismantled.