That was a decisive moment in Lincoln’s career, and that’s the situation he faced when he got up to give his “House Divided” speech on June 16th of 1… - Harry V. Jaffa

The President's proclamation is a mighty blow against the legal positivism that infects our legal establishment, and the moral relativism that pervades our society. But this can only be the beginning of a far greater struggle than that against the physical danger of terrorism. It means taking up once again the burden Lincoln bore, in reasserting the truth of the Declaration, against the "positive good" theory of slavery, and against the still more deadly theory that majorities, and not the difference between right and wrong, should decide the future of slavery.

[S]lavery existed among the Americans largely because of the action of the crown. For the king to have been complicit in the importation of slaves into America and then to have attempted to use them in a war against their masters merited condemnation in its own right. In no way did such condemnation imply a justification of slavery itself.

And the war was a terrible war, but it was a war for human freedom, and if the South had succeeded and if slavery had been extended, the United States, or part of it, might very well have been on the side of Hitler in the Second World War. We would not have been the bastion of freedom we have been in the twentieth century.