Krugman on Chinese currency policy and purchasing power parity

Since I linked earlier to a post arguing that the Chinese currency seemed not that undervalued based on Balassa-Samuelson considerations involving the relative prices of traded and nontraded goods, thought I should link to Paul Krugman's fairly persuasive counterargument---which is basically, look at their current account surplus: they're exporting savings.  Here's his op-ed on the subject.