From Hon. Judge Michael W. McConnell's majority opinion, INITIATIVE AND REFERENDUM INSTITUTE v. WALKER, 450 F.3d 1082 (10th Cir 2006):
One of the Fathers' cardinal concerns was that democratic government not lead to tyrannical rule by a majority over a minority. "When a majority is included in a faction, the form of popular government . . . enables it to sacrifice to its ruling passion or interest both the public good and the rights of other citizens." The Federalist No. 10, at 106 (J. Madison) (Hamilton ed. 1868). The Founders did not think the problem of majority abuse of minorities was limited to those in government: they were particularly worried about the ways in which a majority of the people could impose their will impose on a minority. "The prescriptions in favor of liberty, ought to be levelled against that quarter where the greatest danger lies, namely, that which possesses the highest prerogative of power: But this is not found in either the executive or legislative departments of government, but in the body of the people, operating by the majority against the minority." James Madison, Speech of James Madison to House of Representatives (June 8, 1789) in Daniel A. Farber & Suzanna Sherry,A History of the American Constitution 227, 229 (1990).
Or, we can just quote someone who once said, "Democracy is two wolves and a lamb voting on what to have for lunch." I'll leave you with an amusing spinoff from that quote:
A Democracy: Three wolves and a sheep voting on dinner.
A Republic: The flock gets to vote for which wolves vote on dinner.
A Constitutional Republic: Voting on dinner is expressly forbidden, and the sheep are armed.
Federal Government: The means by which the sheep will be fooled into voting for a Democracy.
Freedom: Two very hungry wolves looking for dinner and finding a very well-informed and well-armed sheep.