Daniel W. Crofts, "Seward, William Henry," American National Biography Online, February 2000, http://www.anb.org/articles/04/04-00898.html.
Seward and Lincoln were the two most important leaders spawned by the intersection of antebellum idealism and partisan politics. Lincoln, of course, will always overshadow Seward. Before 1860, however, Seward eclipsed Lincoln. Seward was governor of New York while Lincoln toiled in the Illinois legislature; Seward was the most prominent antislavery leader in the U.S. Senate when Lincoln's national stature, such as it was, resulted from a strong but losing Senate race. The war that Seward did his utmost to prevent bound together the oddly juxtaposed duo. At once fulfilling the most explosive promise of the liberal reform agenda and at the same time shattering hopes that moral suasion and enlightened amelioration could propel the engines of political change, war taught Lincoln and Seward that all ultimately depended on having stronger, more durable armies. The would-be "peacemaker," memorably celebrated during the secession crisis by the Quaker poet John Greenleaf Whittier, had to protect from foreign interference a Union war effort that employed unlimited violence to destroy the slave system. Perhaps fittingly, Seward remained ambivalent about his legacy.