John Russell Maguire (July 27, 1897 - November 10, 1966) of Greenwich, Connecticut was a former Wall Street broker, oilman, munitions manufacturer and publisher of The American Mercury. Maguire began as an investor in the Mercury and purchased it outright in August 1952 from William Bradford Huie turning it into a type of conservative Readers Digest.
Maguire financially helped in the distribution of the book The Iron Curtain Over America by John Beaty. Also he was a supporter of Merwin K. Hart and Allen A. Zoll, of American Patriots, Inc. This group was labeled as "fascist" by the U.S. Attorney General.
The 1950s issues of The American Mercury edited by American nationalist Russell Maguire can be read here: 
- Our Lord Has A Message For You, American Mercury Magazine, (1957)