What is the difference between a democracy, a republic and a federation?

These are
really not necessarily three
different things.  A democracy, a republic, and a federation are
not
different things in the sense that a car, a tree, and a ball are.  Instead, the three
are
different in the sense that a car, a sports car, and a Mercedes are
different things.  Let us
examine why this is so.

A
democracy and a republic are essentially the same
thing.  In theory, there
are some differences between the two, but in practice in the modern
world,
they are the same thing.  In theory a democracy is a system in which the

people...