What role of slavery/slaveholders in the development of the Constitution?

Answer 1

It was critical, but not how you think. At the time of the constitutional crisis that ended the articles of confederation, literally thousands of white Americans had been sold into slavery by the Barbery Pirates. It is estimated that at one point or another up to 175,000 white Americans were affected. This is the reason that the North, which was maritime, formed such a strong abolition movement. The inability of the separate states to fight the pirates created the constitutional crisis. It wasn't until Jefferson, however, that the nation was strong enough to end the imprisonment of Americans. You still hear echoes of this in the Marine Corps Hymn "...to the shores of Tripoli."

I would suggest reading Power, Faith and Fantasy: America in the Middle East 1776-Present by Michael Oren. It is quite good.

Slaveholders had to balance the impetus against slavery in the North with their economic interests. However, without the Tripolitan pirates, I doubt the US Constitution would exist.