> It's striking to consider the self-delusion that must have been necessary for people at the time to believe in such wildly inconsistent notions as "inalienable rights" and slavery.

Perhaps they simply viewed one as the goal to strive towards, and the other as the current, unfortunate state of reality. Especially given that they had a civil war not six decades after Jefferson's presidency, and paid a high price in their own blood to secure those rights.

Edit: By 'they', I meant people in general, not specifically Washington and Jefferson.