Creating fair, transparent and genuinely democratic modes of decentralized decision-making has been a key concern for many developers and users of blockchains. This article evaluates several popular methods of maintaining consensus and achieving decentralized decision-making on blockchain networks in order to assess the extent to which blockchains challenge the norms of the liberal-democratic order. In particular, it compares and contrasts Proof-of-Work, Proof-of-Stake and Practical Byzantine Fault Tolerance consensus mechanisms, assessing not just how they operate in a technical sense but also (and most important) the political, economic and social dimensions of these different blockchain governance strategies. This comparison highlights efforts by blockchain communities to redefine or push the bounds of democracy, as well as the challenges they have faced in their efforts to create digital democracies that do not reproduce the same economic and social inequalities present in traditional democratic systems.