Gettysburg Address and analysis

Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal. Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived and so dedicated, can long endure. We are met on a great battle-field of that war. We have come to dedicate a portion of that field, as …

…human equality from the Declaration of Independence and redefined the Civil War as a struggle not just for the Union, but as a new "birth of freedom" that would bring equality to all of its citizens. Lincoln's central argument is that the Union soldiers at Gettysburg "sacrificed their lives to the cause of self-determination, but he never mentions the word Union in his speech because he wanted the country to stay united as a nation.