A part of my family tree authored the the Wilmot Proviso that was put forth in the House in 1846.
Do you have any notes, journals, or diaries from their work? If so, your are in high cotton with primary sources.
No notes, journals, or diaries, but Wiki says the handwritten draft of the Wilmot Proviso is in the Library of Congress. It was drafted by Jacob Brinkerhoff and introduced by David Wilmot.
Just to be clear, I am not a direct descendant of Jacob Brinkerhoff, but rather a descendant of Jacob Brinkerhoff's grandfather or great grandfather. I would need to do a little more research to find out for sure how we are related.
Searching Google books brings up this reference, page 234. An interesting few pages of reading.
