The beginning of the United States Postal Service's operation was a very important time in US history. The increased tension over low wages and poor working conditions caused a massive movement which was supported by the Civil Rights Movement. These activists and their communication with the government helped negotiate a contract, and on July 1st, 1971 it replaced the cabinet-level post office into the federal agency as we all know today as the United States Postal Service.
Rural Carrier, 1908. United States Postal Service