 Lucas reported directly to the president on the sentiments of the Spaniards in those cities toward the United States, in preparation for Jefferson's efforts at westward expansion.With strong support from President Jefferson, Lucas was elected as a Republican to the Eighth and Ninth Congresses and served until his resignation in 1805, before the assembling of the Ninth Congress.He moved to St. Louis (then part of the Louisiana Territory), having been appointed district judge for the District of Louisiana (which became Missouri Territory in 1812), and served from 1805 until 1820, when he resigned.