"'Twas in a Pennsylvania town not very long ago, Men struck against reduction of their pay." The mill owner intends to starve the union into submission; in the process, "Father was killed by the Pinkerton men." The singer appeals to politicians to help
For the details of the Homestead Strike, see "The Homestead Strike."
Incidentally, the Pinkertons were not above murder if it met their ends. A famous example was the case of Frank and Jesse James and their mother and stepfather, Dr. Reuben Samuel and Zerelda Cole James Samuel. On January 28, 1875, a gang of Pinkertons firebombed their home in hopes of catching the James brothers. They didn't -- but they did kill Archie Peyton Samuel and do such damage to Mrs. Samuel's hand that it had to be amputated (see Ted P. Yeatman, _Frank and Jesse James: The Story Behind the Legend_, pp. 134-137).
The Pinkertons were eventually charged with murder (Yeatman, p. 143), but the case never came to trial (p. 147). - RBW