Would William Seward have been able to beat Stephen Douglass for the North's electoral votes in 1860 had Lincoln not wowed Republicans with his Cooper Union speech? And, had Douglass won, how would a “Popular Sovereignty” United States have evolved thereafter? But: Harold Holzer: ‘Abraham Lincoln did triumph in New York. He delivered a learned, witty, and exquisitely reasoned address that electrified his elite audience and, more important, reverberated in newspapers and pamphlets alike until it reached tens of thousands of Republican voters across the North. He had arrived at Cooper Union a politician with more defeats than victories, but he departed politically reborn…’ <https://www.americanheritage.com/speech-made-man>
Lincoln's description of the South in this speech is unsurpassed as a description of today's Republican party.