John - The first colonist came ashore in 1607. Considering that as the starting point it was more than 200 years. (I know we didn't have slaves at the time). I state "finally" because salvery was an issue prior to our separation from England.
(cut and paste warning)
-From the Library of Congress:

The American Anti-Slavery Society was established in 1833, but abolitionist sentiment antedated the republic. For example, the charter of Georgia prohibited slavery, and many of its settlers fought a losing battle against allowing it in the colony, Before independence, Quakers, most black Christians, and other religious groups argued that slavery was incompatible with Christ's teaching. Moreover, a number of revolutionaries saw the glaring contradiction between demanding freedom for themselves while holding slaves.

I understand your post in context. I don't bemoan our actions in history. I only accept that we were responsible for some heinous attrocities.