By the 20th century, Philadelphia had become known as "corrupt and contented", with a complacent population and an entrenched Republican political machine. The first major reform came in 1917 when outrage over the election-year murder of a police officer led to the shrinking of the Philadelphia City Council from two houses to just one. In July 1919, Philadelphia was one of more than 36 industrial cities nationally to suffer a race riot of ethnic whites against blacks during Red Summer, in post-World War I unrest, as recent immigrants competed with blacks for jobs. In the 1920s, the public flouting of Prohibition laws, mob violence, and police involvement in illegal activities led to the appointment of Brigadier General Smedley Butler of the U.S. Marine Corps as director of public safety, but political pressure prevented any long-term success in fighting crime and corruption.

Which political party controlled Philadelphia in the early 20th century?