Rath on 20 June 2009
China/USA. The world can only be made unstable by having two opposing superpowers, having one superpower is stable but two always seems to lead to competition.
To be honest though, there isn't any real threat to world stability at the moment. China is growing but the fact that Europe (an economic superpower) and the USA (an economic and military superpower) are reasonably close (despite their disagreements) meaning that the situation should remain fairly stable with the West remaining the dominant superpower.
North Korea and Iran aren't threats to world stability, more just to regional stability.
