Short answer: Yes. James Madison argued that a democracy can host tyranny if power becomes concentrated in one set of hands or if the branches are not properly checked and balanced. He warned that tyranny can emerge not only from an external conqueror but from internal accumulation of legislative, executive, and judicial powers in a single group or institution, or from ordinary majorities overruling minority rights. He proposed structural safeguards—separation of powers, checks and balances, federalism, and a constitutional framework—to prevent such tyranny. Context and explanation

• Madison’s central concern: concentrated power. In his writings, especially The Federalist Papers, he repeatedly argues that mixing and balancing powers among branches is essential to avoid tyranny, whether the danger comes from a single ruler or from the aggregation of power within one faction. This is captured in the famous line often summarized as a warning against “the accumulation of all powers” in the same hands. Even within a democracy, if the same actors control multiple branches or if institutions fail to constrain each other, tyranny becomes possible.

• Tyranny of the majority vs. tyranny by government: Madison recognized risks from both organized majorities and from unchecked government power. He argued that purely majoritarian rule can oppress minorities, while unchecked branches can abuse power regardless of how the public votes. This dual concern underpins his design for constitutional restraint and minority protections.

• Practical safeguards in a democracy: to deter tyranny, Madison advocated for:
  • Distinct and independent branches (legislative, executive, judicial) with defined powers.
  • Balanced and overlapping jurisdictions so no single branch can unilaterally overrule the others.
  • Federalism to disperse power between national and state governments, creating additional layers of accountability.
  • Mechanisms like impeachment, appointment processes, and judicial review to create checks on power.

• Common contemporary summaries: modern references to Madison’s worry about tyranny in democracies emphasize “the tyranny of the majority” and the structural design of government to prevent it. These discussions often quote Madison’s idea that concentrating legislative, executive, and judicial powers in the same hands would be dangerously tyrannical, and thus the US Constitution’s separation of powers aims to prevent that outcome.

If you’d like, I can tailor this to a specific passage or construct a concise quotation-and-interpretation brief with direct citations from The Federalist and related Madison scholarship.