This foray into the East, where Lincoln was still a relative mystery, was for him a crucial moment. Still an unannounced candidate for president, he recognized an opportunity to display himself, clarify his views on urgent questions of the day, and sense the viability of his national candidacy. He would speak in the wake of John Brown’s raid the previous October, which had galvanized Southern fears of slave insurrections and brought a heightened sense of isolation to the South. At the Cooper Institute, Lincoln sought to address the consuming issue of whether the federal government had the constitutional power to control slavery in the western territories. He also had to deal with Southern distrust of the Republican party, which had been formed just six years earlier by anti-slavery activists. Finally, Lincoln considered the moral question of slavery, which he found intrinsic to any discussion of Southern desires and Northern proposals. His remarks were not designed to placate the South but to make clear where he stood—and where he thought the Union should stand.
