Republicanism is a perverted form of democracy.
It is a representative democracy in which government is by the consent of the people. In short, it is a true test of Democracy.
Kingship, aristocracy and constitutional government are the true constitutional forms but they all have perversions that come to being when the rulers of these governments are catering self-interest instead of the common interest. Kingship turns to tyranny when perverted, aristocracy turns to oligarchy and democracy is the perversion of the constitutional government of many. Democracy is the rule of the many poor who work for the interest of the needy while oligarchy is the rule of the few rich that take only their interest in account as rulers. And tyranny, the perversion of monarchy is a constitution formed for the interest of the one tyrannical ruler.