Abstract: Liberal democracies sometimes have to face political deadlock and political crisis, however, the liberal polity doctrine, unexpectedly, lacks a theoy of political deadlock and political crisis. Free negotiation and majority decision are usually regarded as the core rules of political decisionin the liberal polity doctrine, but these rules may encounter three typical political stalemates: disintegration of the political community, nomial conflict on the supremacy, and virtual conflict on the supremacy. If a political regime in a political deadlock, simultaneously,has to cope with economic crises, political rebellions,or external wars, there might be a holistic political crisis or a total regime crisis.But the liberal polity doctrine actually has rich theoretical resources to prevent and overcome political crises, including state theory, institutional theory, theory of rule of law, defensive democracy theory, theory of state of emergency, and so on. Based on these theoretical resources, the liberal polity is more likely to prevent and overcome potential political deadlock and political crisis.