Abstract: In The American Commonwealth (1888), James Bryce identified a political regime-type that he called “government by public opinion,” and argued that the United States had developed it to a greater degree than any other constitutional democracy then extant. Bryce’s analysis entails that familiar propositions about the relationship between public opinion and the constitutional order – many stemming from Publius – must be questioned, and perhaps heavily qualified or discarded. Bryce argues that the basic Madisonian strategy for channeling and containing majoritarian opinions and passions, by means of checks and balances and an extended republic, has perverse results; it strengthens rather than containing the force of public opinion. The power of mass opinion in America thus results, in part, from the very safeguards the framers put into place against it. Once in place, government by public opinion sets both a lower bound and an upper bound on the performance of the American democracy, ensuring that it performs tolerably well but also preventing it from performing better still. In Bryce’s paradoxical assessment, “the American democracy is not better just because it is so good.”