"The Constitution was written to protect the rights of individuals and limit the powers of government. In other words, it was intended to preserve liberty. Not only did the Founders not intend for public policy to be determined democratically, they actively tried to design their new government to prevent public policy from being directed by the demands of its citizens. They recognized that liberty could be compromised by democracy, and that the will of the majority had the potential to be just as tyrannical as a king or dictator."
The government has no power that that an individual does not have other than those enumerated and granted to it by law. That law is the constitution so long as we uphold it and the politicians follow it. To say that a republic and a democracy are similar in every aspect except one can be explained as follows. In a republic the sovereignty is in each individual. In a democracy the sovereignty is in the group.