The Child Labor Amendment emerged from the 1920's Debate over the issue. On the opposing side were urban Catholics & Populists, in support were most Republicans but also Socialists.
The debate can be summed up as Jefferson v. Washington D.C.
Section 1. The Congress shall have power to limit, regulate, and prohibit the labor of persons under eighteen years of age.
Section 2. The power of the several States is unimpaired by this article except that the operation of State laws shall be suspended to the extent necessary to give effect to legislation enacted by the Congress.
I am undecided on the Child Labor Amendment - Smart aka Reuven.