A republic is the simplest and most direct form of government ever devised. It is Rousseau's Social contract in action – a tacit agreement among a group of people to follow a certain set of rules for their own protection and comfort. Republics are self governing because it is to each citizen's advantage to obey the rules.
The core of a republic is the law, in America's case, the Constitution of the United States. The Constitution is the United States, and every elected official and every member of the military takes an oath to protect and defend the Constitution – not the government. In a republic, the government's only job is to enforce the Constitution.
Republics demand a certain type of people. A republican must be honest – not only honest with others but, more importantly, honest with himself. Self-honesty requires a dedication to truth and a rejection of fictions and fantasies that cloud one's perception and dull one's integrity. Republicans, in other words, are practical, pragmatic people, who stand with both feet firmly planted in reality.
Pragmatism, of course, requires awareness, and a republican is well informed. Republicans are not easily swayed or dissuaded because they have long ago made their peace with the facts of life. Nor are they easily dismayed. A republican knows what works and what doesn't work, and he uses that knowledge to accurately predict the outcomes of his actions and of the actions of others.
In short, a republican is a human being. In the final analysis, we are all republicans. But some of us have allowed ourselves to be seduced by the siren call of democracy into sailing the republic into the rocks of Fascism.