It's important to acknowledge just how much randomness goes into the process every year - some years the US team is very strong, other years some of the competi

It's important to acknowledge just how much randomness goes into the process every year - some years the US team is very strong, other years some of the competitors have a bad day. Students graduate, or decide to pursue a different summer activity, and there often isn't anyone on the same level to replace them. Saying that the US "slipped" to third is just nonsense. The fact that China's performance in the IMO is so consistent year after year is a bit mind-boggling, to be honest. I suspect that part of their dominance is a heavy focus on algebra, which is all about consistently getting the job done. Top US students are more likely to have studied "fun" math, like combinatorics, geometry, or number theory - and even if you are a superstar at combinatorics, you can still miss an easy combinatorics problem if you happen not to see the right way to look at it.