The new month being February - and particularly because it's the bicentennial counting from an 1809 birth year - it's time for the annual worship of all things Abraham Lincoln, the president who is a textbook hero for having ended chattel slavery. There are hundreds of books on every aspect of Lincoln's signature achievement except one.
There's less than a dozen books on the validity of his preferred method - war - for ending it.
There's only one book seriously discussing Lincoln's use of military tribunals, newspaper shutdowns, imprisonment and executions of civilians, suspension of habeas corpus, deliberate collateral civilian damage as war policy, and a host of similar activities far more frequently than the recent Bush administration has been so extensively criticized for - and there's almost no discussion of his mid-war objective shift: from union-saving to slave-freeing. Yet you never hear the gentry-left chanting "Lincoln lied, people died."
I would suggest that the overwhelming presidential blunder of the Civil-War period was the failure of his predecessor President James Buchanan; and to a far greater extent, Lincoln himself, to seek an economic solution to the slavery problem.
Both of those well-informed gentlemen were well aware of the declining profitability of slavery during the pre-war decade, to the point where slavery in the Old South was then profitable only as a breed-and-sell business model and slavery in the New South was profitable only on the newest and largest plantations.
Both knew, as students of contemporary economics, that the profitability of slavery was declining as mechanization advanced, the price of slaves increased, cheap European labor was coming in, and contemporary attitudes were changing, so that the North was no longer much interested in enforcing the Fugitive Slave Law to subsidize, at no charge, the South's "Peculiar Institution."
We know all these facts today thanks to a few historical researchers who have written extensively on the profitability-of-slavery question, but those presidents knew the same facts first hand - by 1865 it was all moot.