.... at the time the U.S. Constitution was written, the militia in the south was known by another name: the slave patrol, and virtually all men of age served in its ranks at one point or another. As far back as 1680 in Virginia, the militias were organized to prevent:
“…the frequent meetings of considerable numbers of negroe slaves, under pretence of feasts and burialls is judged of dangerous consequence.” (sic)
In other words, the Virginia Militia was tasked with breaking up slave rebellions by busting any slave who might be organizing one. It even gave ‘incentive’ to men to serve on the militia: any freed colored person (black, Native American, or any other), if caught fleeing by the Militiaman, would be turned over to them as property, enslaved. A very effective incentive in colonial Virginia.
By 1755, the Militia was established not only as a foundation to enforce slavery in the south, but it was a structure which it could be expanded if need be. Countless records of captured free people of color, even people such as the Irish, were pressed as slaves under the system.