 Root was a member of the New York State Senate (Middle D.) from 1812 to 1815, sitting in the 35th, 36th, 37th and 38th New York State Legislatures.In 1815, Root contested successfully the election of John Adams to the 14th United States Congress, and took his seat on December 26, 1815, served until March 3, 1817, and was Chairman of the Committee on Expenditures in the War Department.He was again a member of the State Assembly (Delaware Co.) in 1818, 1819, 1820 and 1820–21; and was a delegate to the New York State Constitutional Convention of 1821.