Why might president lincoln have begun the gettysburg address by noting that the country was ‘'dedicated to the proposition that all men are created equal''?

Lincoln alluded to the idea that "all men are created equal" in his opening as a means to establish what the Union is fighting for during this Civil War. In the Gettysburg Address, he goes on to discuss how the Union should not let these soldiers who died at the Battle of Gettysburg to die in vain. Instead he insists that we continue on this fight in order to truly make America a country in which all men are treated equal, regardless of race.

Lincoln feels that this is a pivotal moment in the Civil War, as the events taking place during this time will determine whether or not America will continue to exist as a country based on the idea that all men should have the opportunity to pursue life, liberty, and the pursuit of happiness.