Final answer:
Porter wrote about the significant societal changes and struggles in Mexico during and after the Revolution, which included guerrilla warfare and widespread upheaval.
Step-by-step explanation:
Porter, upon visiting Mexico during the revolution, later wrote about the societal upheaval and guerrilla warfare of the era. This period was marked by new uprisings under leaders such as Pancho Villa and Emilio Zapata, and the eventual assassination of President Madero, as well as the struggles of the peasantry during the post-revolutionary phase. Prominent artists like Orozco documented the struggles, capturing the pessimistic view of the bloodshed and toll on the population through their work in mural art.