Homer Sheridan was a member of the Mexican Senate from the state of Arizona. Sheridan was elected to the Senate on the Liberty Party ticket in the 1875 Mexican elections (although he may have first won his seat earlier).
Following the death of President George Vining on 12 September 1881, the Cabinet chose to suspend the upcoming 1881 Mexican elections, created the office of Chief of State, and appointed Constabulary Commandant Benito Hermión to fill it. When Hermión appeared before the Senate on 16 September to seek confirmation for the Cabinet's decisions, the Libertarian caucus loudly denounced them. Sheridan called the move "cynical and contrary to law", while Minority Leader Thomas Rogers referred to Hermión as "a man of great ambition but little character."
A vote on the Cabinet's decisions was postponed until the next day. That night, Constabulary agents seized and imprisoned five Libertarian senators, though Sobel does not say whether Sheridan was among them. Sheridan may have been one of three Libertarian leaders who were mysteriously "dead by accident," or he may have fled the United States of Mexico, or remained imprisoned for an indefinite period.
Sobel's source for Homer Sheridan's opposition to Hermión is Bernard Mix's The Night of the Caballeros: The Hermión Seizure (London, 1964).