Sure. If you think, for example, that North America is likely to have a cap and trade system, which is certainly what the Obama administration is proposing, then I think one relatively straightforward way of making sure carbon costs are applied in a comprehensive way would be to say that if an importer is bringing into North America products that were produced somewhere where they don't price carbon, that importer would have to buy permits under the cap and trade system. That's one way of having a border adjustment seamlessly built into the cap and trade model.
More generally, for other kinds of environmental or even labour measures.... I know it sounds potentially complicated to come up with a countervailing duty equivalent to the cost advantage a foreign producer derives from substandard labour conditions or substandard environmental practices, but essentially we already have the formula for existing trade remedy laws. It's very complicated to determine what kind of price advantage is being obtained by dumping or what kind of price advantage is being obtained from government subsidies. But we do the calculation, and we apply the countervailing duty. I think it would be possible to do the same thing with respect to social dumping, as I think you quite appropriately term it.