What's obvious and over-looked.
Our collect future whether we like it or not is one where population growth and levels eventually will have to decline drastically - either by "natural" catastrophe, or design. In either case the global economy as it was designed and as we have come to know it - will collapse, because it is absolutely dependent on growth. Any nation that has come to this realization, recognizes that if it doesn't want to be caught in the global collapse caused by population and market decline - it has to create and control a scenario in which it creates rapid population declines and then grows into that opportunity of space and resources. Current technology suggest that the most efficient way of accomplishing this is through biological warfare. Since this would be rather obvious and cause retaliation prior to the demise of enemy/target nations - the aggressor nation is likely to also show serious (but calculated and controlled) population loss by the disease bio-weapon used - thereby confusing the target nations as to whom is the aggressor. It's only logical and already over populated China would benefit most from implementing this scenario.