There have been various claims that Cermak rather than Roosevelt was the intended target of the assassination. These theories speculate that organized crime in Chicago wanted to assassinate Cermak either because he opposed them strongly, or because he had taken bribes from them but not delivered. None of these theories have been generally accepted.

Cermak changed the face of Chicago politics. Before him, Chicago was a Republican town. After him, solidly Democrat thence forward. How much change he actually affected in Chicago in his brief stint as mayor between 1931 and 1933 is probably not that much. He was crippled by the tax strike of the Association of Real Estate Tax Payers, which hurt Chicago finances throughout his term.

Cermak's rise to power was definitely linked to ethnic politics. He organized the Czech community of Chicago (of which he was a member - Main other Czech community politician of note in Illinois was Otto Kerner Jr., Cermak's son in law, who became governor of Illinois).

The Czech's were not one of the largest ethnic communities in Chicago, but they were one of the first (after the Irish) to organize politically, and Cermak rallied an alliance of the Czechs, Poles, Italians, Ukranians, Jews, and African Americans to win against Big Bill Thompson and his mostly Irish demographic base in the mayoral elections.