The slave patrols were emphatically not the militia. The militias had just fought in the Revolution. The states wanted to preserve their militias in case they had to defend themselves against a foreign power or against some president who became a tyrant. Thus the Second Amendment promised that the states could keep their well-regulated militias. (See a discussion of this in my article “A Well Regulated Militia.”) Sometimes the militia acted as a slave patrol; sometimes militia service might include slave-patrol duty, but they were emphatically not the same thing.
Hartmann claims that “By the time the Constitution was ratified, hundreds of substantial slave uprisings had occurred across the South.” Does he have any evidence for this claim? Such evidence would revolutionize our understanding of Colonial and early national history. But there is no evidence for such a claim, because these “substantial slave uprisings” never took place. There were some small instances of slave violence in the Colonial period, although escape was the most common form of slave resistance. There was only one true “slave uprising” in the South, the Stono Rebellion in South Carolina, which took place in September of 1739, a half century before the Constitution was ratified. There were not “hundreds” of such rebellions, only very few, and only Stono was “substantial.” On this issue Hartmann is simply wrong.
Hartmann’s statement that Patrick Henry “opposed slavery on principle” is almost amusing! In fact, in opposing ratification, Henry argued that the Constitution threatened slavery. Henry owned slaves throughout his adult life, and did not free them either during his life (like some Southern patriots) or even at his death (like Washington). He made numerous speeches defending slavery at the Virginia ratifying convention and argued against ratification on the grounds that the national government would someday free the slaves of Virginia.
Hartmann argues that the “main concern” of those who wrote the Second Amendment “was that Article 1, Section 8 of the newly-proposed Constitution, which gave the federal government the power to raise and supervise a militia, could also allow that federal militia to subsume their state militias and change them from slavery-enforcing institutions into something that could even, one day, free the slaves.” There is not a shred of evidence that anyone thought this. Moreover, it is hard to imagine under Article I how that would work.
If anything, Northern anti-federalists opposed the Constitution because it would force Northerners to march south and suppress slave rebellions. The use of state militias (although not Northern ones) to suppress Nat Turner’s rebellion in 1831, and the use of the U.S. military to suppress John Brown’s raid in 1859, illustrates this issue.
Hartmann asserts that in the “lead-up” to the Revolution Lord Dunmore issued a proclamation freeing slaves in Virginia. In fact, Dunmore issued his proclamation after the Revolution began and fighting had broken out, not in the “run-up” to it. In writing about history, it is important to get the chronology straight. Since British policy supported slavery and British policy was designed (however poorly) to keep the colonists in the Empire, it is hard to imagine why Hartmann would believe that before the Revolution the Royal Governor of Virginia would start freeing slaves.
The Constitution (as opposed to the Bill of Rights) protected slavery in many ways, through the Three-Fifths Clause, the Slave Trade Clause, the Domestic Insurrection Clause, the Fugitive Slave Clause and the amendment provisions. The Fifth Amendment protected slave property, as Chief Justice Taney says in Dred Scott (1857), but most of the rest of the Bill of Rights is not about slavery in any important ways.