child labor
While it is the Republican Party ultimately pushing for the return of significant child labor to America, the problem is located most deeply within migrant communities, where government oversight is.
Back when I was doing the research for Empire of Timber, I ran across a story in a timber journal about a child laborer from sometime around 1900. See, the.

Breaker boys, Woodward Coal Mines, Kingston, Pennsylvania., ca. 1900
The full on Republican embrace of forcing children to work says everything you need to know about the party and about how it sees the future, i.e., the glory days.
On April 16, 1836, Massachusetts passed the nation's first law limiting child labor. It required that children under the age of 15 working in factories be given three months off.
Boys selling newspapers, Brooklyn Bridge, 1908
For once, the massive amount of child labor in this nation is receiving attention. I talk about it frequently, but as a third-rate historian on a top 100 political science.
Not enough workers? Well, sure, we could pay more. Or we could open the doors to the millions of immigrants who wish to come and work here. But instead, Republicans.