Pork barrel is the appropriation – the act of setting apart something for its application to a particular usage, to the exclusion of all other uses – of government spending for localized projects secured solely or primarily to bring money to a representative’s district.
The usage originated in American English. In election campaigns, the term is used in derogatory fashion to attack opponents. Scholars, however, use it as a technical term regarding legislative control of local appropriations.
The term pork barrel politics usually refers to spending that is intended to benefit constituents of a politician in return for their political support, either in the form of campaign contributions or votes.
After the American Civil War, the term came to be used in a derogatory sense.
By the 1870s, references to pork were common in Congress, and the term was further popularized by a 1919 article by Chester Collins Maxey who claimed that the phrase originated in a pre-Civil War practice of giving slaves a barrel of salt pork as a reward and requiring them to compete among themselves to get their share of the handout.
Generally, a barrel of salt pork was a common larder item in 19th century households, and could be used as a measure of the family’s financial well-being. For example, in his 1845 novel The Chainbearer, James Fenimore Cooper wrote:
“I hold a family to be in a desperate way, when the mother can see the bottom of the pork barrel.”