what is the third and final clain that the author makes to support the argument about national service

National service would teach young people about teamwork and service.

This statement is taken from Abraham Lincoln’s second inaugural address.  This statement appears at a time within the speech where he is talking about slavery and the civil war and how horrible the offenses of each are.  However, he alludes to the notion that war might be the will of God in order to get rid of slavery.   This relates to his purpose because he is the president of a divided country warring against itself, and it is something for which many would fault a nation’s leader.  Thus, even though he wishes there were no war, he notes that war might the purpose of the Almighty.