I would think that the Chinese, whom I believe are our principle, long-term threat and are establishing relationships and plans to this end (to thwart and end American dominance) around the world, would wait at least until sometime after the Olympics and until their own military power is stronger.
OTOH, if the opportunity arises, and if Syria and Iran go after it and have any measure of success...and if the Chinese and N. Koreans have the contingencies and plans in place, they may well advance such a time table if they think the chance for success against those aims is there.
In which case, if the war in the Mid-East explodes and we are pulled more generally into it with larger mobilizations and more troops and assetts...then watch the Korean penninusla. If that goes off too, and we are scrambling even more to respond to it...then watch for the PRC's move.
What I object to is the opinion that China will secretly be on our side, because they so value the "world economy".
They may or may not value it, but I firmly believe that if they could bring about our demise by trashing the world economy, they would not think twice.