Well, actually, the United States was a world leader in the abolition movement of the time. The Constitutional reference you're looking for is from Article 1, Section 9, Clause 1: "The migration or importation of such persons as any of the states now existing shall think proper to admit, shall not be prohibited by the Congress prior to the year one thousand eight hundred and eight, but a tax or duty may be imposed on such importation, not exceeding ten dollars for each person." As I noted in an earlier post in this very thread, the United States was actually ahead of the United Kingdom in this regard, as it took until 1807 for Parliament to pass the Slave Trade Act. Otherwise, I think your post was excellent and dead-on. Of course, the War was about slavery. It went way beyond a mere economic grievance, which can rationally be sorted out, to verge into the realm of the quasi-religious, where no disagreement is permissible. This is the money quote: ETA: Your reference to bills of attainder came from the same Article and Section (Clause 3).