Its a Mistake to think this Fault 
[tyranny] is proper only to Monarchies; 
Other Forms of Government are liable to it, 
as well as that. 
For where-ever the Power 
that is put in any hands for 
the Government of the People, and 
the Preservation of their Properties, 
is applied to other ends, and 
made use of to impoverish, 
harass, or subdue them to 
the Arbitrary and Irregular Commands of 
those that have it: 
There it presently becomes Tyranny, 
whether those that thus use it are one or many.
-- John Locke (1632-1704). 
English philosopher and political theorist
Source: Two Treatises on Government, 1690