The best answer to this comes from the extremely able pen of Michael Burlingame, the most prolific Lincoln scholar of our time. In Burlingame’s estimation, Lincoln’s rather sad personal story allowed him to become the paterfamilias, the father of the nation.

Having endured a very painful relationship with his own father, and a rather difficult marriage, Lincoln devoted himself to the tasks of parenthood. He was a loving parent to Willie, who was something of a carbon copy of himself. He had a distant relationship with Robert, who, as many writers see it, was “all Todd and no Lincoln.” When Willie died, Lincoln devoted himself to Tad, but he also became the father of the people.