The Child Labor Amendment failed because it did not meet the requisite number of states for ratification. Passage required 38 states, but it stalled at 28, notes Mental Floss.
The first child labor bill was the Keating-Owen bill of 1916 and became the Keating-Owen Act; it was passed by Congress, signed into law by President Woodrow Wilson and ruled unconstitutional by the Supreme Court. The Supreme Court also struck down a second bill passed in 1918; it was called the Child Labor Tax Law. In each case, the federal government argued for child labor regulation using the interstate commerce clause, but the states claimed it was an infringement on the 10th Amendment, reports Our Documents.
In 1933, President Franklin D. Roosevelt appointed Frances Perkins as secretary of labor. Secretary Perkins advocated introducing bills pertaining to child labor, the minimum wage and a maximum number of hours. Because of her efforts, President Roosevelt signed the Fair Labor Standards Act of 1938. The act banned repressive child labor. It set a minimum wage at 25 cents an hour and a 44-hour workweek. Although the FLSA was challenged in the Supreme Court, the act was deemed constitutional. The FLSA became effective on Oct. 24, 1938, according to the U.S. Department of Labor.