Marxism tends to undermine the notions of heroism and moralism intrinsic to juvenile biography as a genre. The repository of civic virtue is not the the individual hero, but the class to which he or she politically adheres. Moral precepts are not universally applicable, but have a class content. The hero is not he who can never tell a lie, but the one who lies unflinchingly to the police while never lying to the class. The hero is not the one who is most distinguished in her virtues, but the one who aids the class in finding its own virtues by giving unstintingly of her capacities. And because the struggle has not yet found its way to final victory, the most obvious heroes are the tragic ones--the type of heroism hardest to translate into the juvenile mind.
More than most Marxists, Rosa Luxemburg's life lends itself to juvenile biography because of her propensity to refer her own triumphs to the class, to speak and act according to an ethical imperative derived from the class struggle, and to portray defeats as moments on the way to the final victory.
For precisely that reason, it is remarkably difficult to write about those moments in which she fell the furthest short of her own standards, e.g., the period immediately before and after the second Congress of the RSDLP, when she squandered the opportunity to unify the Polish party with the Russians as she had been insisting was necessary for her entire political life, made the question of opposition to Polish self-determination into a sectarian point d'honneur, and then misrepresented the substance of the disagreements between Lenin and herself to an international audience.
Explaining that in terms that a child can understand may well be impossible. It's hard enough for me to understand, as an adult who has made a close study of the period.
This creates the temptation to gloss over it completely and write as if it never happened. But in becoming a parent, I have translated the Marxist dictum of "never lie to the working class" into another dictum that is even harder to live by: Never lie to your kids.