Final answer:
The ideology at stake for Lincoln emphasized the enduring principles of liberty, equality, and democracy. His focus was on the nation's commitment to these ideals, ensuring a union that upholds them, especially highlighted in the Gettysburg Address and other speeches.
Step-by-step explanation:
The ideology at stake for President Abraham Lincoln, as seen in the famous last lines of his speeches, especially the Gettysburg Address, extended beyond preserving the nation state; it centered on a set of principles embedded in the American constitution and national character. These principles were liberty, equality, and democracy, concepts that Lincoln believed the Civil War was fought to uphold. The war was not just about reuniting the North and the South but was also a test of whether the nation, conceived in liberty and dedicated to the proposition that all men are created equal, could survive the internal strife and emerge stronger and more united. Lincoln's speeches demonstrate his commitment to reconciling the nation while ensuring that the principles of liberty and equality for which so many had sacrificed would endure and expand, like the extension of voting rights to Black men.
Thus, for Lincoln, the Civil War was as much an ideological struggle as it was a physical one. It was about preserving the American ideology and ensuring that the government of the people, by the people, for the people, would not perish from the earth. Therefore, the very principles upon which the nation was founded were what truly were at stake according to Lincoln.