On the evening of February 27, 1860, a near capacity crowd gathered inside the Great Hall at the Cooper Union in New York City. Nearly 1,500 New Yorkers curious about the man from Springfield, Ill., came to hear him speak. In a brilliantly vivid recounting of the 7,700-word address in his book “Lincoln at Cooper Union,” Harold Holzer persuasively argues that it was this speech that made Abraham Lincoln president.