the differences between the principles of republicanism and democracy.

Democracy: government by the people, especially rule of the majority.

Republic: A government in which the supreme power is vested in the people and exercised by them directly or indirectly through a system of representation usually involving periodically held free elections. a government having a chief of state who is not a monarch and who in modern times is usually a president : a political unit (as a nation) having such a form of government.