“The Cop and the Anthem” is a short story that belongs to the category of naturalism. Naturalist literature centers on the idea that people’s fates in life are predetermined (by nature, social forces, or both). Many 19th-and 20th-century naturalist writers told bleak stories of the lives of impoverished and disenfranchised people who were unable to change their circumstances no matter how they tried. That “The Cop and the Anthem” ends with Soapy committing himself to freeing himself from a life of crime, only to be immediately arrested and imprisoned for the simple act of loitering, makes this a naturalist story. O. Henry is communicating that it is near impossible for homeless people to escape the cycles of poverty and crime.
In addition to being a work of naturalist fiction, “The Cop and the Anthem” can also be seen as a work of social criticism. This comes across in passages like the following, in which O. Henry critiques the institution of philanthropy:
In Soapy’s opinion the Law was more benign than Philanthropy […] [T]o one of Soapy’s proud spirit the gifts of charity are encumbered. If not in coin you must pay in humiliation of spirit for every benefit received at the hands of philanthropy. As Cæsar had his Brutus, every bed of charity must have its toll of a bath, every loaf of bread its compensation of a private and personal inquisition.
This passage is notable in that, for most of the story, Soapy is zipping around trying to get arrested and not pausing to offer social commentary, yet here a very direct critique of philanthropy comes through. (This is only one part of Soapy’s tirade.) It is likely that O. Henry himself took issue with the ways philanthropy “encumbered” those who received social support with “private and personal inquisition[s].” What he means is: rather than simply offering money, food, or housing to people living in poverty with no questions asked, philanthropists often require recipients of their support to prove their worthiness. O. Henry also critiques policing as an unjust and ineffective institution throughout the story.