People often are under the impression that the United States in 1789 was replete with ideas of racial superiority. They usually hold those views on very tenuous grounds...
OK, so I take it that what you want to convince a reader of this post to believe is that the United States in 1789 was not replete with ideas of racial superiority. If so, your argument certainly doesn't refute--or even address--that claim. An argument about the framers of the Constitution wouldn't say anything about the general state of racist ideas in America in 1789--any more than an argument about the beliefs of a President's cabinet tells us about the prevalence of beliefs in the general population.
In this speech, Abraham Lincoln looks at every one of the 39 framers of the Constitution and asks: "When and if they had the chance to vote to restrict or abolish slavery, how did they vote?" If I am not mistaken, 22 had the chance to do it and 21 voted against slavery -- to paraphrase Lincoln, this is a clear majority. I'd argue that this near uninanimity would apply to the rest of the 39 founders -- which is also a point Lincoln try to make in that same speech.
Lincoln was arguing that the framers of the Constitution intended for slavery to be limited and hence should not be extended into the western states. That doesn't form an argument about the prevalence of racist beliefs in the early United States--and indeed, it doesn't say anything about whether the framers themselves were racist or not. I may decide to become a murderer, for example, but limit myself to murdering only people in the American South. I am still no less a murderer.
...you cannot erase the record of votes which taken together would have killed the institution had all those motions passed.
This seems to be saying something impossible on its face, though perhaps I don't understand what you mean. If the framers voted, and various measures to kill slavery did not pass, then all their votes together weren't sufficient to kill the institution of slavery.
So, in 1789, the people who crafted the Constitution actually believed slavery was an abhorrent institution.
This is not in evidence. Perhaps they thought it was useless in the Northern states. Perhaps they thought the economic benefit long-term would become more of a liability.
The history of slavery in the United States is not the history of why Southern States were backward... It's the history of a class of southern planters and of a political party that built its influence by defending the interest of that class of wealthy southern planters.
You say this is relevant history, but I don't see it. Your thesis could be either true or false whether or not this is true or false.
Tell me, young man, which group today is likelier to make that kind of argument? Conservatives and moderate liberals will speak like Lincoln: free labor is better than slavery.
Far right conservatives of a particular persuasion will tend to argue that slavery ought to be restored, so that those they consider inferior can serve the master race. On the other hand, I think you'd be hard pressed to find even very extreme liberals who'd make a similar argument.
They will disagree on how much should collectively be done to promote opportunities and on how to best do it, but they will agree that spoon feeding people is a very bad idea.
Are you seriously trying to draw a comparison between using extremes of force to kidnap and enslave a human being on the one hand, and offering them public assistance on the other?
Radicals on the other hand... they absolutely will make the Fitzhugh argument. I'm not sure Noam Chomsky knows that when he talked about wage slavery, he was in agreement with some of the despicable, disgusting people that have ever spoken about politics in the United States: 19th century Democrats.
This just seems confused. Radicals don't argue that slavery is better than work. Fitzhugh's argument was obviously specious--it based on a clearly false premise (since plenty of slaveowners did all sorts of horrific things to their slaves that reduced or entirely negated their ability to work). Worse, Fitzhugh conceives of the value of human beings in the same terms as the value of property, whereas democratic socialists argue that human beings have intrinsic moral worth that is incommensurable with property.