[67] In 1837, he declared, "[The] Institution of slavery is founded on both injustice and bad policy, but the promulgation of abolition doctrines tends rather to increase than abate its evils."[68] He echoed Henry Clay's support for the American Colonization Society which advocated a program of abolition in conjunction with settling freed slaves in Liberia.[69]
He was admitted to the Illinois bar in 1836,[70] and moved to Springfield and began to practice law under John T. Stuart, Mary Todd's cousin.[71] Lincoln emerged as a formidable trial combatant during cross-examinations and closing arguments. He partnered several years with Stephen T. Logan, and in 1844 began his practice with William Herndon, "a studious young man".[72]

U.S. House of Representatives (1847–1849)
Lincoln in his late 30s as a member of the U.S. House of Representatives. Photo taken by one of Lincoln's law students around 1846.
True to his record, Lincoln professed to friends in 1861 to be "an old line Whig, a disciple of Henry Clay".[73] Their party favored economic modernization in banking, tariffs to fund internal improvements including railroads, and urbanization.