During the war, Grant established a commendable record, studied the tactics and strategies of Scott and Taylor, and emerged as a seasoned officer, writing in his memoirs that this is how he learned much about military leadership. In retrospect, although he respected Scott, he identified his leadership style with Taylor's. However, Grant also wrote that the Mexican war was morally unjust and that the territorial gains were designed to expand slavery, stating, "I was bitterly opposed to the measure ... and to this day, regard the war which resulted as one of the most unjust ever waged by a stronger against a weaker nation." He opined that the Civil War was divine punishment on the U.S. for its aggression against Mexico. During the war, Grant discovered his "moral courage" and began to consider a career in the army.