In The Power Broker, Robert Moses emerges into a political world that is dominated by a force named Tammany Hall. Originating as a fraternal organization, Tammany Hall evolved into a political machine that dominated New York City politics for much of the 19th and early 20th centuries. Tammany Hall originated in the Tammany Society, which was founded in 1789 as a fraternal organization with Native American motifs. Initially, it served as a social club for immigrants, particularly Irish immigrants fleeing the Great Famine of the mid-19th century. Under the leadership of figures like William M. Tweed, Tammany Hall transformed from a benevolent society into a potent political machine.

Tammany Hall’s ascent to political dominance was fueled by several key factors. First was its ability to mobilize New York immigrant communities, particularly the burgeoning Irish population, through a network of ward bosses and local organizers. Tammany provided vital services and assistance to immigrants, cultivating a loyal voter base in return. Secondly, Tammany Hall practiced (and, to some extent, mastered) the art of patronage politics. Through its control of city government, Tammany distributed jobs, contracts, and other favors to its supporters, cementing their loyalty and ensuring a steady stream of votes come election time.