Former Econlog blogger Arnold Kling's latest post is titled "Why Did the South Not Converge?" In it, he quotes from a book by Ira Katznelson and goes on to suggest various factors behind the failure of per capita incomes in the northern and southern states to converge.
Here's the problem: according to Robert J. Barro and Xavier Sala i Martin, they did converge. Their paper is here. Their paper was published in 1990 and I guess there could be some more-recent research showing that their data are wrong.
When I was writing my review of Acemoglu and Robinson's Why Nations Fail, my economic historian friend Jeff Hummel told me that it's widely accepted among economic historians that per capita incomes post-Civil War converged. Are Jeff Hummel and I wrong? Is there research on this that overturns this result?
UPDATE: A regular reader of Econlog has sent me this link to another paper by Barro and Sala i Martin. On page 122 is a nice graph of the convergence from 1880 on.