The House of the Spirits presents a literary version of a political fiasco, namely the events leading to the 1973 coup d'état in Chile that removed Socialist President Salvador Allende from power. Politics begin to crop up in the second chapter of the novel, and become more and more central to the plot as the novel progresses. The characters debate and wage campaigns over questions of society and class, women's rights, and the idea of justice. While the author's political stance on this chapter of Chilean history is pretty clear, it's interesting that she manages to present the opposing point of view – still a prominent one in Chile today – in a somewhat sympathetic light as well.
Alba's political involvement and acts of resistance against the military dictatorship are primarily motivated by other characters, like her boyfriend Miguel, the spirit of her grandmother, and her friend Ana Díaz. Alba doesn't have any real political conviction of her own – she's essentially a passive character.
Though the author takes a definite political stance in the novel, she still manages to present the opposing point of view in a sympathetic light by explaining its rationale.