You know how Trump “serves” as president rather than “rules” as one? Why this expression? It could be to hide the tyrannical nature of the state. But it’s equally possible that it’s a remnant of the institution of “public” slavery, as described by M.L. Bush:
Among the slaves in service, easily the best treated were the military servitors of the Ottoman Empire, Safavid Persia, and a number of Islamic states situated in North and West Africa.
These slaves comprised a ruling elite in possession of power as well as wealth. Their essential purpose was to give the ruler a means of action independent of his leading subjects and one that he could fully control, although, in reality, he tended to fall under the sway of his slaves. …
Not surprisingly, public slaves were better treated than private slaves, simply because they tended to be engaged as servitors, many of them as elite soldiers, administrators, or household officials, whereas private slaves were mostly engaged in some form of manual labor. (10-11)
He properly differentiates this meaning of publicness from that attached to “the forced-labor systems developed in the twentieth century by totalitarian regimes where, in contrast to slavery, the acquisition of labor involved no capital outlay and the absence of replacement costs removed all restraint on its maltreatment. In these circumstances, it did not matter much if labor was worked to death. To treat slaves in that manner made no economic sense since it simply destroyed a capital asset.” (13-14)