He was admitted to the Illinois bar in 1881 and commenced his practice in Chicago. He held several local offices before being elected as a congressman: • Member of the
Oakland Board of Education in Chicago (1887) • Attorney for
Hyde Park and the South Park commissioners of Chicago • Chairman of the Illinois State Republican convention (1894) • Member of the
City Council of Chicago (1892–1896) • Master in
chancery of the
Superior Court of Cook County • Chairman of the Republican county conventions at Chicago (1895, 1902) • Elected as Republican (1896) to the 55th Congress with 13 successive terms
Service in the House • Chairman, Committee on Elections No. 1 (58th–60th Congresses) • Committee on Interstate and Foreign Commerce (61st Congress) • Committee on Women Suffrage (66th Congress) • Minority Leader (62nd–65th Congresses)
Notable legislation .1911–1919 Congressman Mann was one of the sponsors of the
Mann-Elkins Act, which gave more power to the
Interstate Commerce Commission to regulate railroad rates. He is probably best known for his authorship of the
Mann Act of 1910, which was a reaction to the "
white slavery" issue and prohibited transportation of women between states for purposes of
prostitution. He introduced legislation that became the
Pure Food and Drugs Act of 1906. He was considered to be a leader in the cause of amending the
United States Constitution to grant
suffrage to women. However, he was quoted as saying, "'They should have been at home where they belonged,' referring to the women in the pageant." He was a leading opponent of the
Harrison Narcotics Tax Act and
Prohibition, despite the popularity of such legislation amongst his fellow Midwestern progressives. == Death ==