I'm reading a paper by Mike Munger where he makes the claim that the postal campaign was a failure b/c it ossified positions on slavery and basically drove out or extinguished any dissent of the slavery question in the south. When I've read about it before I've always read that it was a success b/c it raised the question on the national scale.

What's the current scholarly thought on the campaign? My guess is "it's more complicated than either of those positions" is the current thinking. What are the complications and can you recommend any articles or books on the topic?