The US launched a probe into Chinese exports of aluminium products on Wednesday night but postponed a decision on whether to include the country’s exchange rate policy in its inquiry.

The investigation, announced by the commerce department, will unfold over the next few months, with an initial determination scheduled for May 17. It threatens to reignite tensions between the US and China over the value of the renminbi after a period of relative calm between the two countries on the issue. (FT)

Two things. First, for American readers, “aluminium” is actually “aluminum.” Do not be confused by archaic spelling, even if the Britspeak version sounds more like an element than the normal, English version. Being American means you don’t have to worry about, or apologize for, inconsistency.

Second, this marks the second time now that the U.S. government has passed up a chance to render a judgment on China’s forex policy. The first opportunity was the U.S. Treasury Report that includes a list of forex “manipulators.” The report’s publication has turned into a regular event of “will they or won’t they?” that rivals the old days of Congressional debate over PNTR, which ended when China joined the WTO.

Earlier this month, after extensive negotiations, the U.S. announced that they would hold off on publication of the report until a later date. Hard to say what sort of deal, which had a lot to do with the recent Nuclear Summit and Iran sanctions, was struck; I still think there is a danger that Obama is getting played here by Beijing.

Now we have this decision on the aluminum case. The administration is being consistent, at least, in pushing all currency-related matters away for the time being.

The big question now is how long will they wait for Beijing to make a move? If nothing happens on the RMB this summer, what will be the reaction from the White House? This summer will see a great deal of electioneering by Congressional incumbents and wannabes — the election is in November — and the RMB issue will come up in many of the races.