The immorality of slavery is secondary to its economic viability.
The creation of cheap mechanized labor via mechanics and electricity is the great liberator. Elimination or substantial reduction of that inexpensive energy source will necessarily revive slavery as a viable economic tool.
Slavery was not vanquished in the 19th century because it was wrong, it was vanquished because it was no longer necessary and profitable, with muscle power being vastly inferior to mechanized power. The South lost the Civil war because it relied on slave labor or muscle labor which was simply not as productive as the mechanized energy utilized in the north. The South could not produce enough resources to sustain a prolonged war, not in a society where a pastoral life of ease for a few requires the work of hundreds to sustain. In the North, with manufacturing roaring and the use of mechanized labor, it could vastly out-produce the South.
This is not to disparage or minimize the people who gave their lives to eradicate slavery in the U.S., but merely to note that slavery is as old as recorded history. Great achievements from the great pyramids to the Roman aqueducts to the great cathedrals required the backbreaking toil of thousands living at subsistence to produce what can be produced today by a few hundred highly paid and skilled laborers who have a standard of living that would be the envy of kings of yore. Slavery was not invented in the US. It was conquered in the U.S. by the availability of inexpensive mechanized energy.
If you have to till your soil by hand with a hoe, you will be lucky if you can produce enough food to feed your family, much less produce an abundance allowing for the sale or trade of foodstuff to obtain the other necessities of life.
Any substantial reduction of mechanized energy will inevitably increase the amount of manual labor required to produce food and other products and will eventually make slavery profitable again.
Think the thought through, it is self-evident. It need not be proven, though it could be. Perhaps it should be to deduce the exact level of mechanized energy output that would make the subsistence provision for a fellow human being in exchange for their labor necessary and profitable. Because, I assure you, that is the goal of the green movement and the liberals who are striving to eliminate the cheapest means of energy production. If that energy is continuously reduced, the threshold at which slave labor again becomes viable will be breached.
Until the US releases its true energy output via oil, coal and nuclear power, we will remain on a steady course toward tyranny and slavery. It is not a side effect, it is the objective of all opposition to inexpensive energy. It is about force, power and work, who does it and who controls it. Those who seek to control power, force and work, seek to control you by reducing your access to those very commodities.
World English Dictionary
— n , pl -gies
1. intensity or vitality of action or expression; forcefulness
2. capacity or tendency for intense activity; vigour
3. vigorous or intense action; exertion
a. the capacity of a body or system to do work
b. E a measure of this capacity, expressed as the work that it does in changing to some specified reference state. It is measured in joules (SI units)
5. kinetic energy See also potential energy a source of power
[C16: from Late Latin energīa, from Greek energeia activity, from energos effective, from en- ² + ergon work]
1 [urg] Show IPA, noun Physics.
the centimeter-gram-second unit of work or energy, equal to the work done by a force of one dyne when its point of application moves through a distance of one centimeter in the direction of the force; 10− 7 joule.
Origin: 1870–75; < Greek érgon work
— n the cgs unit of force; the force that imparts an acceleration of 1 centimetre per second per second to a mass of 1 gram. 1 dyne is equivalent to 10 -5 newton or 7.233 × 10 -5 poundal
[C19: from French, from Greek dunamis power, force]