Obviously, if there had not been the marriage of Sarah Bush Johnston to Thomas Lincoln, there would never have been a President Abraham Lincoln.
And, where would the world have been now?
And, Doris Kearns Goodwin added this important observation: "Lincoln’s early intimacy with tragic loss reinforced a melancholy temperament. Yet his familiarity with pain and personal disappointment imbued him with a strength and understanding of human frailty. Moreover, Lincoln possessed a life-affirming humor and profound resilience that lightened his despair and fortified his will."
"So very difficult a matter is it to trace and find out the truth of anything by history." -- Plutarch