Horse trading, in its literal sense, refers to the buying and selling of horses, also called "horse dealing". Due to the difficulties in evaluating the merits of a horse offered for sale, the sale of horses offered great opportunities for dishonesty, leading to use of the term horse trading (or horsetrading) to refer to complex bargaining or other transactions, such as political vote trading. It was expected that horse sellers would capitalize on these opportunities and so those who dealt in horses gained a reputation for underhand business practices.
As standards for ethical business declined in the United States in the Gilded Age, the activities of horse traders came increasingly to be seen as the natural and, in part, desirable product of a competitive market rather than as symptoms of moral depravity. In an 1893 New York Times editorial criticizing a proposed law to make it illegal for a newspaper to falsely state its circulation figures, the author declared that "if the lying were stopped by law, the business of horse trading would come to an end, and the country taverns and groceries in the Winter season would be deprived even of the limited eventfulness which they now enjoy".
Vote trading is the practice of voting for or against another person's bill, position on a more general issue, or favored candidate in exchange for the other person's vote for or against a position, proposal, or candidate that one supports.
Vote trading frequently occurs between and among members of legislative bodies. For example, Congressman A might vote for a dam in Congressman B's district in exchange for Congressman B's vote for farm subsidies in Congressman A's district. One of the first examples of vote trading to occur in the United States was the Compromise of 1790, in which Thomas Jefferson made a deal with James Madison and Alexander Hamilton to move the capital from New York to a site along the Potomac (after a lengthy stay in Philadelphia) in exchange for federal assumption of debts incurred by the states in the Revolutionary War. Hindrances to vote trading in the U.S. Congress include its bicameral structure and the geographic representation basis of its members. Vote trading is encouraged, however, by Congress's relatively loose party discipline which facilitates policy cross-overs by individual congressmen, in sharp contrast to European countries.