A Republic is best explained by first explaining a Democracy.
In a pure Democracy the people argue among themselves. The argument is resolved by voting. 51 beats 49. Whatever the majority says is imposed upon the minority. The minority has no rights. The majority doesn't need rights. In other words, the sovereignty is placed in the group. It is the group that is not accountable to higher authority. The members of the group are the citizens, and they must obey the dictates of the group. In the long run, a Democracy becomes a dictatorship of the majority.
Except for two points, a Republic is identical in all aspects to a Democracy. In a Republic the people argue among themselves, just as is done in a Democracy. The argument is resolved by voting. However, because each individual People is sovereign, the decision of the majority can only be advice to the individual. The logic is simple: If the group can impose its will upon the individual, the individual would no longer be sovereign, and you would no longer have a Republic; it would be converted into a Democracy. At best, the group is limited to advising the individual. If a group is unreasonable, the individual sovereign is free to ignore the advice. In the long run, a republic ensures the freedom of the individual.
The other feature of a republic is that the individual may act directly, or he can delegate a task to his representatives. In a Republic, that is why you can use the government courts, or you can create your own court.
