Senator Joseph M. Dixon of Montana managed Theodore Roosevelt’s campaign for the 1912 Republican presidential nomination and Roosevelt’s presidential campaign as the Progressive Party candidate. By challenging his own party’s incumbent president, Roosevelt guaranteed a tense and vitriolic campaign characterized by mixed loyalties and political infighting. Such an atmosphere helps explain Senator Dixon’s letter to Frank Harper, Roosevelt’s secretary, in March 1912, a few weeks after Roosevelt officially entered the race for the Republican presidential nomination.
Letter from Joseph M. Dixon to Frank Harper, March 12, 1912. From the Library of Congress Manuscript Division.
Dixon requests that a cipher be used in confidential telegrams to the National Roosevelt Committee, the headquarters for Roosevelt’s nomination campaign. It is unknown what provoked Dixon into the cloak and dagger world of encrypted communications; perhaps it was a leak to the press, betrayal by a perceived ally, or simply an overabundance of caution. Unfortunately for the campaign, Dixon’s cipher was so rudimentary that most schoolchildren have experimented with a similar system.
Dixon provides the directions for a substitution cipher known as the Caesar shift, named after Julius Caesar who supposedly used this system during the Gallic Wars. The cipher uses a simple shift in the order of the alphabet to encrypt a message; Caesar used a four letter shift, Dixon shifts one letter. When encrypting for Dixon, A would appear as B, B as C, and so on. This is about as basic as a cipher can be but Dixon wisely adds another layer of security by instructing that messages be broken into groups of five letters, ignoring punctuation and spaces. After encryption and grouping, THEODORE ROOSEVELT would appear as the title of this post.
No evidence for the actual use of Dixon’s cipher has been found in our collections but cryptography is present in other forms. For example, Elihu Root, then serving as Secretary of War, forwarded a report to President Roosevelt regarding a 1903 military expedition along the coast of Lake Lanao on the island of Mindanao, Philippines. The report is available in the original government code and in the decrypted plain text.
Telegram from Elihu Root to Theodore Roosevelt, April 11, 1903. From the Library of Congress Manuscript Division.
Lunde, Paul. The Book of Codes: Understanding the World of Hidden Messages : an Illustrated Guide to Signs, Symbols, Ciphers, and Secret Languages. Berkeley, CA: University of California Press, 2009.