== rape == 

 This is just terrible writing: "Its motivation, he said, was to rape a virgin" 

 Sumner proposed an analogy in which Slavery rapes the Virgin Territory to produce a Slave State as its illegitimate offspring. He didn't say the Act's motivation was rape. He may have said the Act's impact was analogous to rape or even akin to rape. But he's not identifying the Act itself as an act of rape.