As usurpation is the exercise of power, which another hath a right to; so tyranny is the exercise of power beyond right, which no body can have a right to. And this is making use of the power any one has in his hands, not for the good of those who are under it, but for his own private separate advantage. When the governor, however intitled, makes not the law, but his will, the rule; and his commands and actions are not directed to the preservation of the properties of his people, but the satisfaction of his own ambition, revenge, covetousness, or any other irregular passion.
John Locke, Second Treatise of Government
barrack-obama, law, tyrrany