When there is money to be made... When the possibility of Patriotic PR comes about... When the president wants to show that he has a bit more than a couple of shrivled raisen-balls...

When there's a real danger that OPEC will repeg the price of oil to the much stronger euro instead of the dollar, causing the US economy to behave like any other economy with that trade balance and debt load would, i.e. crash in hyperinflation?

Peter