Slotkin : (On the situation in late 1861) So it's a poisonous situation, and there is actually a serious proposal to make McClellan a dictator, and what they mean by that is that they would - not that there would be a military coup but that they would pass a law vesting the power to run the war effort in McClellan and formally take - in a sense taking it away from Lincoln.
NPR: And he wrote a lot of letters to his wife, many of which have endured for historians like yourself. What do they tell us about his (McClellan's) musings about taking control of the republic?
Slotkin on McClellan's Harrison Landing Letter:
And he really - McClellan in effect makes three important demands of Lincoln. First, that the administration reject any move against slavery, and the letter says in a kind of threatening way that if anything radical is done about slavery, the army itself will dissolve - that is, the soldiers will refuse to fight.
And the second thing he says, and this is kind of a legalistic point, but it's an important one, he says that a war of subjugation would be against the Constitution - that is, it's not - Lincoln can't treat the Southerners as rebels, that as the Southern territory is liberated from the Confederates, Southerners have to be restored to their political rights, so that no sooner are they liberated than ex-Confederates can start voting for Democrats.
And the third thing he says is that Lincoln should appoint a commander-in-chief - that is, a soldier commander-in-chief - and give him power to act essentially without interference from the political - from the civilian government. And it's stunning. Basically a defeated general is asking the president to give up his political power and surrender his own party's interest and platform to the platform and interests of the opposition.