(This post was originally meant as a response to Dave’s, but it became unwieldy in that form due to its length. So I posted it here instead.)
Dave, your post was helpful for me as I try to come to terms with Arendt’s complicated relation to Marxism. But I want to reflect on the passage you quoted from Bensaïd at the end of your post. I mean to very briefly indicate that Bensaïd’s championing of a certain kind of revolutionary politics in the 21st century stands challenged by another contemporary possibility for such politics.
As Dave notes, Bensaïd identifies two “essential revolutionary conceptions for this epoch” within Lenin’s work: (a) the distinction “representative revolutionary party (or parties)”/” working class”, and (b) the need for a democratic centralism. Indeed, he suggests that without centralism one cannot properly speak of a democratic revolutionary politics. It seems that “representation” is deeply connected to “centralization” as a key mechanism for achieving the latter; Bensaïd writes in the same interview that “a party … is the best agent of conscious unification.”
Recent movements have been calling precisely these two “essential conceptions” into question. Upheavals in in America, Argentina, India, Canada, and elsewhere (Occupy, the December 19th-20th movement, and so on) from the 90s to today, and with roots in past forms of protest, contain various but strong traces of an anarchistic, prefigurative politics. By that I mean they are often structured around demands for and attempts to realize decentralized, non-representative, affinity- and consensus-based politics as well as around a rejection of hierarchy. Such a politics attempts to found social formations which are constituted within radically democratic practices, tacitly and sometimes explicitly calling into question a politics which would mimic the overarching, centralizing, hierarchical power-structures found in the state and capital and requiring leaders alienated from and ruling a represented “base.” Theorists like Day, Graeber, Holloway, and others have worked to develop a critique of a centralized radical politics and its relationship to the state on the basis of those movements. Indeed some (like Graeber) have therefore suggested that the most important conceptual tools for understanding revolutionary politics in the recent world lie not in Marxism/Leninism, but in anarchism, given the role of that tradition and activists within it in inspiring and shaping recent movements (although this is perhaps itself a hyperbolic and problematic claim).
Much more remains to be said about recent movements: for instance, an analysis of their limits and contradictions which would examine whether or not they survive the critique of non-centralized politics leveled by Bensaïd. This post is only meant to offer for discussion the idea that alternatives have emerged relative to the conceptions of revolutionary politics that Bensaïd has posited as “essential … for this epoch” and which can be productively understood as constituting a radical challenge to such concepts.
 The following sources chart the emergence of some of these “prefigurative” movements as well as their demands: Chris Dixon, “Building ‘Another Politics’: The Contemporary Anti-Authoritarian Current in the US and Canada,” Anarchist Studies 20, no. 1 (2012): 32–60; Marina Sitrin, Horizontalism: voices of popular power in Argentina (Edinburgh, Scotland; Oakland, CA: AK Press, 2006); Richard J. F Day, Gramsci Is Dead: Anarchist Currents in the Newest Social Movements (London; Ann Arbor, MI; Toronto: Pluto Press ; Between the Lines, 2005); David Graeber, “Anarchism, or The Revolutionary Movement of the 21st Century,” accessed February 12, 2014, http://zcomm.org/znetarticle/anarchism-or-the-revolutionary-movement-of-the-twenty-first-century-by-david-graeber/; Jérôme E. Roos and Leonidas Oikonomakis, “We Are Everywhere! The Autonomous Roots of the Real Democracy Movement,” ROAR: Reflections on a Revolution, accessed September 30, 2013, http://roarmag.org/2013/08/autonomous-roots-real-democracy-movement/.
 Day, Gramsci Is Dead Anarchist Currents in the Newest Social Movements, 8-9.
 Graeber, “Anarchism, or The Revolutionary Movement of the 21st Century.”