Upon these momentous, undecided questions Lincoln, in his high authority as president, had to bring his judgment, his action, and his influence into settled shape. Deep in the heart of these unsettled regions he set his camp, and toiled away his life. This heroic and patriotic act may be called a detail of constitutional interpretation. But it was for Lincoln a labor of Hercules. It opened a gigantic controversy. The land was convulsed with contending explications. Views, held essential to the vital honor of separate sections of the land, were in essential hostility. As the dissension deepened, two questions rose, outstanding above the rest:--the Constitutional integrity of the several States (might States secede?); and the Constitutional rights of slavery (should slavery spread?). Both these problems were mortally acute in 1861. Both were still in hand in 1865. Under the Constitution could the Union be legitimately dissolved? Under the Constitution should slavery be permanently approved? To both these questions Southern leaders answered, Yes. To both these questions Lincoln answered, No. Of these two questions and asseverations, it is plain to see that the second is the more profound. So this second inaugural affirms: "Somehow" slavery was the cause of the secession and the war. This "all knew." Upon this pivot, all the chances and contentions of the great debate were compelled to turn. Here lay all the meaning of the war. All those awful battles were trembling, struggling arguments; thrilling, impassioned affirmations striving to finally and forever decide whether human slavery was justified to spread. Here was a supreme divergence of conviction, and a supreme debate. In all the realm of social morals, no divergence and no debate could be more radical. Into this supreme contention Lincoln was compelled to enter. To some conclusion that should be supreme he was, by his official station and responsibility, compelled to lead. To find his way through such a controversy, and to guide the land through all that strife to some sovereign reconciliation, involved this common citizen in the presidential chair in an assumption and exercise of authority nothing less than sovereign.