[6] Incumbent Democrat Carter Harrison IV had, shortly after his 1903 reelection, declared that he would not seek an additional term in 1905.

[9] He was out-of step with the political tides on this issue, as both parties had come to regularly support the idea of municipal ownership.

[9] Additionally, many Chicagoans were growing impatient with Harrison's inability to resolve the city's traction issue.

[9][10] Even before this rise in public dissatisfaction towards his mayoralty, Harrison had only eked out a relatively narrow margin of victory in the city's previous mayoral election.

[8] At the same time that Harrison was seeing a decline in his political prospects, Edward F. Dunne began to rise in prominence.

[9] Rumors immediately arose that he would challenge Harrison by running as an independent candidate, but Dunne denied this, declaring that he was a loyal Democrat.

[9] Former judge William Prentice (a leader of the Chicago Federation of Labor) said that he would run as an independent candidate in support of municipal ownership unless Dunne was the Democratic nominee.

[9] In November 1904 Dunne declined a nomination from the Municipal Ownership League to run for mayor as a third-party candidate under their banner.

While the Harrison-aligned Democratic Central Committee did not issue any endorsement, Dune was strongly supported by both the Bryan-Altgeld and Hearst wings of the party.

[9] Despite receiving strong buzz as a prospective candidate, alderman William Emmett Dever did not run against Dunne.

[8] In his acceptance speech he declared that his central issue as mayor would be implementing municipal ownership of the city's streetcars.

[12] However, despite Dunne's presence atop the Democratic ticket, the party nominated John Collins for mayor.

[citation needed] A judge on the Cook County Circuit Court, Dunne had no prior executive experience.

[9] He was a contemporary with progressive leaders of both parties in other American cities, including Tom L. Johnson, Samuel M. Jones, Mark Pagan, Hazen Pingree, and Brand Whitlock.

[9] To drive turnout among Democratic voters, Dunne held party rallies in each of the city's wards and delivered remarks aimed at appealing towards strong-Democrats, as well as remarks aimed at winning over the city's ethnic voters.

[8] While de supported making "ample provision for municipal ownership and operation", he stated that he believed that this could only be implemented at a later date when, "the city can be legally and financially able to successfully adopt it".

[9] These included the city's business and banking community, establishment members of the Republican Party, and Republican-leaning newspapers.