A political machine is a political group in which an authoritative boss or small group commands the support of a corps of supporters and businesses (usually campaign workers), who receive rewards for their efforts. The machine's power is based on the ability of the boss or group to get out the vote for their candidates on election day.
Although these elements are common to most political parties and organizations, they are essential to political machines, which rely on hierarchy and rewards for political power, often enforced by a strong party whip structure. Machines sometimes have a political boss, often rely on patronage, the spoils system, "behind-the-scenes" control, and longstanding political ties within the structure of a representative democracy. Machines typically are organized on a permanent basis instead of a single election or event. The term may have a pejorative sense referring to corrupt political machines.
The term "political machine" dates back to the 20th century in the United States, where such organizations have existed in some municipalities and states since the 18th century. Similar machines have been described in Latin America, where the system has been called clientelism or political clientelism (after the similar Clientela relationship in the Roman Republic), especially in rural areas, and also in some African states and other emerging democracies, like postcommunist Eastern European countries. The Swedish Social Democrats have also been referred, to a certain extent, as a "political machine", thanks to its strong presence in "popular houses".