 He studied law, was admitted to the bar in Prince George's County, Maryland about 1836, and returned to St. Mary's County to practice.He served as a member of the Maryland House of Delegates in 1837 and again 1843, and was elected as a Whig to the Twenty-eighth Congress, serving from March 4, 1843 to March 3, 1845.After his tenure in Congress, Causin moved to Annapolis, Maryland, and served as a delegate to the State constitutional convention.