The constitutional nationalism of the Marshall Court reached its peak in 1824 with Gibbons v. Ogden, in which Marshall broadly expounded the commerce clause while striking down New York's steamboat monopoly laws. By 1827, however, a crack in the nationalist consensus revealed itself in Ogden v. Saunders, a contract case that elicited Marshall's first and only dissent on a question of constitutional law.

Marshall's active life outside the courtroom included two longstanding projects: revising his Life of George Washington and preparing an edition of Washington's correspondence. In his own correspondence for these years, Marshall comments on such topics as the causes of the Revolution, the military history of the war, the social scene in Washington, the abolition of slavery, female education, and the novels of Jane Austen.