If you remember, not long after President Bush became president, we had that incident with the US spy plane hugging Chinese airspace, which was bumped by a Chinese jet intercepter and forced to make an emergency landing on Chinese territory. Then just days ago we had a strangely similar incident at sea. Again, just a few months into the tenure of a new president.

Now we have Chinese Prime Minister Wen Jiabao publicly worrying about the safety of the almost $1 trillion of US Treasuries China owns. That they'd have some concern isn't surprising. But having the head of government sound the warning bell is hardly the best approach to preserving confidence in US debt.

This strikes me as all of a piece, pretty unsubtle signaling of a shifting balance of power.

Certainly, it is worth noting that China's export driven economy and massive build up of capital reserves were the fuel behind the US housing bubble. And China's own continued growth is dependent at least for now and for some time into the future on a very receptive US market for its goods. We're in a toxic but mutual embrace.