One of the most common American proverbs, “Never swap horses in midstream,” is indelibly associated with Abraham Lincoln. The observation is a distillation of more extended remarks that Lincoln made on June 9, 1864, to a delegation from the National Union League who had come to the White House to congratulate him on his nomination for a second term as President. What Lincoln said was: “I do not allow myself to suppose that either the convention or the League have concluded to decide that I am either the greatest or best man in America, but rather they have concluded that it is not best to swap horses while crossing the river, and have further concluded that I am not so poor a horse that they might not make a botch of it in trying to swap.”