Which of these publications first demonstrated that journalists would play a role in the Progressive goal of eliminating political machines?

Lincoln Steffens, "Tweed Days in St. Louis," McClure's Magazine (1902)

The publication of Lincoln Steffen, "Tweed Days in St. Louis," McClure's Magazine (1902) is widely heralded as one of the most significant journalist attempts to reform political machines because it rallied middle-class support against "Boss" Tweed and Tammany Hall.