Among the many cases he presided over was the 1820 case of "Polly v. Lasselle", in which he ruled to free all slaves in Indiana. Among his most important and impacting decisions was the case of "State v. Tipton" which severely limited the ability to appeal decisions to higher courts, but significantly decreased the Supreme Court's caseload. In "Deming v. Bullit" he ruled that parties could cancel contracts of sale even after payment was made, provided they refunded the fees. In "Shanklin v. Cooper" he ruled that contracts made in Indiana regarding assets outside of the state were still under Indiana's judicial jurisdiction, although he ruled to overturn his own precedent in the case of "Hunt v. Standart". Because Indiana had only a very limited civil and criminal code during the nineteenth century, Blackford relied heavily on English common law treatises to base his own decisions on, including "Coke's Reports" and "Blackstone's Commentaries". During his lifetime, he amassed a personal library with nearly 2,000 volumes of legal works.