Final answer:
Child labor was prevalent in the nineteenth century due to economic necessity, lack of regulation, and industrialization. Progressive reforms, education laws, and mechanization led to a decline in child labor by the twentieth century.
Step-by-step explanation:
Child labor was more common in the United States in the nineteenth century than it is today due to several socio-economic and legal factors. During the period of rapid industrialization, there were few laws to regulate working conditions or the employment of children. The booming industrial economy and the demand for cheap labor led to the exploitation of young children, often working long hours in dangerous conditions. Families often depended on the income earned by children to make ends meet, so child labor was seen as a necessity.
By the end of the nineteenth century, education laws mandating schooling began to shift children from factories to classrooms. Progressive reforms and a shift towards greater mechanization in factories—which eliminated many of the jobs children could do—further decreased child labor. Efforts by reformers and the establishment of lobby groups gradually led to state and federal laws restricting the use of child labor. However, these were not always enforced and the battle continued well into the twentieth century until federal legislation during the Great Depression formally banned child labor to protect adult jobs.
In summary, the prevalence of child labor in the nineteenth century was due to the necessity of additional family income, lack of legal protections, and the dynamics of industrialization which favored cheap, young laborers before societal values and laws evolved to prioritize education and childhood well-being over economic exploitation.