History has a reactionary bias. To understand history would be to shatter their worldview. For example, Lincoln's first inaugural address makes it clear that the war amongst the states was about maintaining the Union for the sake of taxing the South.

He is the only president to argue for enshrining slavery with a constitutional amendment:

I understand a proposed amendment to the Constitution, which amendment, however, I have not seen, has passed Congress, to the effect that the federal government shall never interfere with the domestic institutions of the States, including that of persons held to service. To avoid misconstruction of what I have said, I depart from my purpose not to speak of particular amendments, so far as to say that holding such a provision to now be implied constitutional law, I have no objection to its being made express and irrevocable.

Here he threatens to invade the south only if they refuse to pay taxes:

In doing this there needs to be no bloodshed or violence; and there shall be none, unless it be forced upon the national authority. The power confided to me will be used to hold, occupy, and possess the property and places belonging to the government, and to collect the duties and imposts; but beyond what may be necessary for these objects, there will be no invasion -- no using of force against or among the people anywhere. Where hostility to the United States in any interior locality, shall be so great and so universal, as to prevent competent resident citizens from holding the Federal offices, there will be no attempt to force obnoxious strangers among the people for that object.