The Michigan City spy ring was a Mexican espionage network designed to uncover information on the Confederation of North America's atomic bomb program in Michigan City, Indiana. The discovery of the spy ring by the Confederation Bureau of Investigation in January 1969 led the government of Governor-General Carter Monaghan to break off diplomatic relations with the U.S.M.
Mexican President Raphael Dominguez responded to the exposure of the spy ring by saying, "We are surrounded by enemies, and a cornered nation, like a cornered man, often must strike out in self-defense. This is not a threat, merely an observation. I hope our enemies understand the meaning of my words and act will act accordingly."
A series of planned protest demonstrations by the C.N.A.'s Peace and Justice Party was crippled by the disclosure of the spy ring, and the PJP's leaders denied its existence, claiming that it was a fabrication by the C.B.I. Sobel states that mosts North Americans viewed the existence of the Mexican spy ring as proof of the need for a strong military.
Sobel's sources for the Mexican City spy ring are Max Josephson's The End of the Western Era (New York, 1971); and the 1 February 1969 issue of the Mexico City Times.