The recent drop in oil and other commodity prices makes it almost a certainty that some unstable commodity-exporting nations will reach a crisis stage in the next few months. The only question is, which countries are likely to erupt first? The Middle East is always a safe bet for an explosion, but there is a very good chance the next eruption will be in Africa, with the most likely location being Congo, followed by Sudan. In Latin America, Argentina is headed for another debt default and financial meltdown, and Venezuela continues to rapidly deteriorate. And there is Russia, which is...