Final answer:
John Locke, Montesquieu, Voltaire, and Rousseau made significant contributions to American democracy through their ideas on natural rights, separation of powers, and questioning of absolute monarchs.
Step-by-step explanation:
John Locke, Montesquieu, Voltaire, and Rousseau made significant contributions to American democracy. John Locke's natural rights theory, which stated that all people are entitled to life, liberty, and property, influenced the Declaration of Independence. Montesquieu's idea of separating powers into branches of government influenced the system of checks and balances in the American government. Voltaire and Rousseau's ideas prompted the questioning of absolute monarchs and paved the way for more democratic ideals.