The Unconstitutionality of Slavery (1845) Book

A curious and remarkable book by a Massachusetts attorney, and proto-libertarian, Lysander Spooner, arguing in 1845 that slavery was unconstitutional. He takes the question from numerous angles, from English common law and statutes in the colonial period, colonial charters, state constitutions after independence, the Declaration of Independence, Article of Confederation, the U.S. Constitution and later state laws.

Basically, Spooner takes an originalist approach, arguing that the specific text of the above constitutions and laws, construed according to the legal canons of interpretation and natural law, cannot be read as allowing slavery. It was a bold approach which won over quite a few adherents in his day, including Frederick Douglass.