The Blocks of Five were groups of electors who sold their votes to the United States Republican Party for the United States presidential election of 1888.
Background
In the Gilded Age, prior to the adoption of the secret ballot in Federal elections, political parties printed ballots and distributed them to their voters, who then cast them at their polling stations. Republican campaigner William Wade Dudley sent a circular on October 24, 1888 to Indiana Republican officials, telling them to "divide the floaters [vote sellers] into blocks of five" and appoint a trusted leader who would be given the money to pay them for their fraud.
The plan was exposed when a railroad official turned one up and it was subsequently publicized. The Republican candidate Benjamin Harrison was elected anyway. The publicity of the notoriously brazen fraud is credited with aiding states' adoption of the secret ballot.