http://en.wikipedia.org/wiki/Thomas_Jefferson_and_slaveryOpposed freeing of slaves. Refused to recognise Haiti. Never freed his own slaves. Had children with his slave girls and refused to free the children. Allowed the wife of his son and their 8 children be sold to 4 separate owners. Disgusting.
I'm really pleased you asked me to get more informed on that.
In 200 years, future generations perhaps will likewise be condemning us for whatever evils we compromised with, evils that we were also born to and are, in large part, trapped by. The point here is that Jefferson was one of the few members of his generation that recognized slavery for what it was and addressed. His peers removed his protests against slavery from his masterpiece.
BTW, Sally Hemings was the half-sister of Jefferson's beloved dead wife. Court historians forget to mention that very human fact. It doesn't absolve Jefferson of his other sins but as far as 18th-19th century slave owners go, Jefferson was leagues beyond his peers.
Judging history by the standards of our day is a good way to miss the more subtle connections of history.

Oh I agree. Times change and morality evolves. Were the old Testament god around today, he'd be locked up for advocating genocide. However, it wasn't me that wheeled out Thomas Jefferson to support an argument against the right to levy taxes.