Citizens and political leaders need to trust that our system of government will guarantee their rights to participate in government, and guarantee their liberties to live their lives as they please, even if they are on the losing side of a vote. These guarantees are at the core of the distinction between constitutionally liberal republics and the bare-bones version of republics.
Political and civil rights enshrined in the Constitution protect people from tyranny by leaders and by political factions. Without this protection, those in power could entrench themselves by reducing the political and civil liberties of those out of power, to the point where they could no longer expect to compete effectively in future elections. Those excluded would face a choice between fighting for their rights, sabotaging those in power, or seceding from the territory it governs.
Excerpted from America: Democracy or Republic?
 Diamond (2003) cites Locke, Montesquieu, and the American Federalists (p. 29).