John F. Kennedy's purpose in writing about Senator Lamar is the same as his purpose in writing Profiles in Courage as a whole. He is trying to point out instances in which political figures demonstrated courage. Kennedy wanted people to see that it was important for political leaders to forego the easy path and instead do what was best for the nation as a whole. What Lamar did was to try to bring about good relations between the North and the South after the Civil War. His constituents generally did not approve of this since they were still upset over the war (Lamar was from Mississippi). But Lamar persevered because that was what he thought was best for the country. This made him an example of the sorts of values Kennedy was trying to promote in the book.