Abstract: Benkler describes the results of a large-scale study of the political media ecosystem duringthe 2016 US presidential campaign and the first year of the Trump presidency. The majorfinding is that the American political media ecosystem is asymmetrically polarized, with aninsular, well-defined right wing, and the rest of the media ecosystem, from the center-right to the far left,forming a single media ecosystem anchored by traditional media organizations like the NewYork Times or the Washington Post. The structure renders the American right moresusceptible to propaganda and disinformation than the left. The chapter then offers ananalysis of why political economy, rather than technology, was the source of thisasymmetry, outlining the interactions between political culture, law and regulation, andcommunications technology that have underwritten the emergence of the propaganda feedbackloop in the right wing of the American media ecosystem, and outlines the structural driversof the present epistemic crisis.