POLITICS, n. A strife of interests masquerading as a contest of principles. The conduct of public affairs for private advantage.

Ambrose Bierce (1842-1914?) American writer and journalist

“Politics,” The Devil’s Dictionary (1911)
    (Source)

Originally published in the "Cynic's Word Book" column in the New York American (1906-03-16), and the "Cynic's Dictionary" column in the San Francisco Examiner (1906-03-21).