I have not previously heard of that second part, regarding expansion. Do you hav...

thesteamboat · on June 26, 2015

Ta-Nahesi Coates recently highlighted a number of sources.

http://www.theatlantic.com/politics/archive/2015/06/what-thi...

For extending slavery beyond the borders of south, see the quotes of Edward Pollard and Albert Gallatin Brown at the end of the post.

elwin · on June 26, 2015

https://en.wikipedia.org/wiki/Golden_Circle_%28proposed_coun...

https://en.wikipedia.org/wiki/Filibuster_%28military%29

If you're looking for a more serious reference, Freehling's Road to Disunion devotes a chapter to the subject.

stevehawk · on June 26, 2015

You realize you just posted a link to an idea created by a secret society headquartered in the North, right?

elwin · on June 26, 2015

That's what I get for citing Wikipedia. But the idea was also brought up by actual southern politicians, particularly in the discussions at the end of the Mexican War.