establish a sense of patriotism and support for the war.
The most likely purpose of including this in the last paragraph is to show support for war. Wilson, at the end of his speech, says that the war hurts people's rights, the sovereignty of the country's government and the right to democracy. Because of this, he said that one must fight to ensure that these rights are not taken from the population even if it costs the peace of the nation. The passage from the text that makes this clearer is: "But law is more precious than peace, and we must fight for the things we always bring closer to our hearts."
