As an anti-federalist delegate to the Virginia convention that considered ratification of the United States Constitution, Monroe opposed ratification, claiming it gave too much power to the central government. He took an active part in the new government, and in 1790 he was elected to the Senate of the first United States Congress, where he joined the Democratic-Republicans. He gained experience as an executive as the Governor of Virginia and rose to national prominence as a diplomat in France, when he helped negotiate the Louisiana Purchase in 1803. During the War of 1812, Monroe served in critical roles as Secretary of State and the Secretary of War under President James Madison.