nally settled in
Jacksonville, Illinois, where he was admitted to the bar in March 1834,
and obtained a large practice. From the first he took an active interest
in politics, identifying himself with the Jackson Democrats, and his
rise was remarkably rapid even for the Middle West of that period. In
February 1835 he was elected public prosecutor of the first judicial
circuit, the most important at that time in Illinois; in 1835 he was one
of several Democrats in Morgan county to favour a state Democratic
convention to elect delegates to the national convention of 1836--an
important move toward party regularity; in December 1836 he became a
member of the state legislature. In 1837 he was appointed by President
Van Buren registrar of the land office at Springfield, which had just
become the state capital. In 1840 he did much to carry the state for Van
Buren; and for a few months he was secretary of state of Illinois. He
was a judge of the supreme court of Illinois from 1841 to 1843. In 1843
he was elected to the national House of Representatives.

In Congress, though one of the youngest members, he at once sprang into
prominence by his clever defence of Jackson during the consideration by
the House of a bill remitting the fine imposed on Jackson for contempt
of court in New Orleans. He was soon recognized as one of the ablest and
most energetic of the Democratic leaders. An enthusiastic believer in
the destiny of his country and more especially of the West, and a
thoroughgoing expansionist, he heartily favoured in Congress the
measures which resulted in the annexation of Texas and in the Mexican
War--in the discussion of the annexation of Texas he suggested as early
as 1845 that the states to be admitted should come in slave or free, as
their people should vote when they applied to Congress for admission,
thus foreshadowing his doctrine of "Popular Sovereignty." He took an
active share in the Oregon controversy, asserting his unalterable
determination, in spite of President Polk's faltering from the
declaration of his party's platform, not to "yield up one inch" of the
territory to Great Britain, and advocating its occupation by a military
force; indeed he consistently regarded Great Britain as the natural and
foremost rival of the United States, the interests of the two nations,
he thought, being always opposed, and few senators fought more
vigorously the Clayton-Bulwer Treaty or Great Britain's reassertion of
the right