According to the US Constitution (before 1865) where was the issue of slavery left
to?

Before 1865, Slavery was between a thriving-dying institute, especially if located in the Southern United States. When slavery was a constant event, cotton was usually the biggest crop to harvest, but there was also other crops to get. For example, there was tobacco, hemp, livestock, corn, wool, wheat, rye, oat, and more to collect for their slave owners. Although, there were also those who worked in the southern city as skilled traders or common laborers. If paid, they were able to buy their freedom, which is why the Southern region had free African-American men (usually men, not woman), as well as some Northern regions. Slaves were forced and had no control over their work, they were supervised all the time when working, and they were threatened or immediately punished by their overseers if seem fit.  Overall these conditions and the lack of freedom, slaves were not powerless victims of their owners and the slave system (in their minds at least).

I hope this helped.