Final answer:
The federal government struggled to address child labor due to the Supreme Court ruling federal laws unconstitutional, powerful business and farm lobbying, a conservative political climate, general prosperity, and the Tenth Amendment which left such powers to the states.
Step-by-step explanation:
The problem of child labor was not effectively addressed by federal legislation for a number of reasons. Initially, states that had implemented their own child labor laws found that goods produced by children in other states were still penetrating their markets, leading to a net loss in jobs and no significant reduction in child labor. The Supreme Court also played a role in inhibiting federal action by declaring that the 1916 law against the interstate shipping of goods made by children was unconstitutional, citing it as a violation of the Tenth Amendment.
Furthermore, during the 1920s, there was a conservative political climate and general prosperity, causing conservative legislatures to vote down anti-child labor laws and the Supreme Court to reverse key provisions that were aimed at limiting child labor. In addition, the business and farming lobbies were so influential that a proposed Constitutional amendment to ban child labor was ratified by only a handful of states. Finally, the Fair Labor Standards Act of 1938 marked a victory for opponents of child labor, banning the interstate trade of goods produced by children under the age of sixteen.