The economy and labor market of the United States

The economy and labor market of the United States underwent massive changes in the late 1800s.  In the industrial north, a growing number of men, women, and children of different racial, ethnic, and occupational backgrounds became wage laborers.  In the agricultural south, many former slaves also became wage laborers working for wealthy landowners and employers. One of the major issues in this time period was the conflict between these workers and their employers, the struggle between labor and capital.  What were some of the major efforts by workers to form unions or political organizations to improve their jobs in the late 1800s? How easy or difficult was it for workers to unite with one another? Why did employers and government officials often resist these efforts and how did it affect the success of these efforts?