This is a great article that focuses more on asking questions than in giving answers. I'm not sure about the final agenda of the author, but it is absolutely thought-provoking. I was a fence-sitter on the issue... now, however, I find myself swayed.
The issue is short-vs. long-term impact of subsidized grain shipment overseas, and the effect that this has had in receiving nations. I am going to see if the UN has any data on the effect on productivity later today.
See what I'm talking about here.