Washington, Dec. 8, 1860Library of CongressGate and north portico of the White House, circa 1859-61 Five Southern gentlemen came calling, anxious to speak with the president of what was, as far as they were concerned, on the brink of becoming a foreign country. For the moment, they all remained American citizens – and members of Congress, no less. But that was a mere technicality. As they strode up the steps to James Buchanan’s second-floor office, they carried themselves with a dignity befitting the founding fathers of a new nation: the independent Republic of South Carolina.The Carolinians’ mission that Saturday was...