A sacrificial lamb is a lamb (or metaphorical parallel) killed or discounted in some way (as in a sacrifice) in order to further some other cause. In typical modern usage, it is a metaphorical reference for a person who has no chance of surviving the challenge ahead, but is placed there for the common good. The term is derived from the traditions of Abrahamic religion where a lamb is a highly valued possession, but is offered to God as a sacrifice to obtain the more highly valued favour of God.
In politics
In politics, a sacrificial lamb candidate is a candidate chosen to contest an election despite the fact that he or she has little chance of victory. The political party thus appoints the person as a sort of "sacrifice" to the stronger opponent.
In some cases fielding a sacrificial lamb candidate can serve as an opportunity for the party to be more creative in choosing a candidate than would normally be considered acceptable in a closely contested race. For example, they may choose a racial or ethnic minority or a person who would otherwise be considered "too risky" in normal circumstances. For instance, Alan Keyes or Geraldine A. Ferraro. In 2004Howard Mills was considered a sacrificial lamb candidate for the U.S. Senate from New York against Chuck Schumer.
In the arts
In cinema and literature, the term sacrificial lamb refers to a supporting character whose sole dramatic purpose is to die, thus galvanizing the protagonist to action and simultaneously demonstrating how evil the villain is. Very often, the sacrificial lamb is a family member, partner, or "old buddy" of the protagonist, with whom he or she has an assumed intimacy, thus requiring no real character development. The term is almost always used critically, with the implication that the character was used transparently as a plot device.