Contract doctrine anchored both constitutional liberty theory and legal education

Evidence

Contract law was also one of the basic building blocks of legal study. (It is to this day.) C. C. Langdell’s first casebook (1871), a milestone in the history of legal education, was a casebook on contract; and Langdell himself worked to develop contract doctrine and the theory of contracts. … To constitutional theorists, free contract was an essential tool of the democratic state, a mighty pillar supporting the palace of liberty; to students and teachers of law, it was the great gate to entry into the palace. — Lawrence M. Friedman, A History of American Law, 3060