I agree with what Professor Dissou has said about setting this up. In a sense, you don't need exactly the same targets to reduce uncertainty. To reduce uncertainty you need to have a target that's credible--and you're going to get there. That will reduce uncertainty.
The issue after that is cost. Then there are the competitiveness effects across the county if, as you say, Canada and the U.S. have similar economic structures. As you know, we're more energy intensive than the U.S., for example, so how should that play itself out if we want to think of it in terms of costs across the countries?
But on uncertainty, the key thing is not whether we have an integrated policy with the U.S. or anything; it's whether we have a target that we know we're going to respect. Once that's in place, uncertainty kind of disappears from the picture. Somehow in this an implicit contract is being talked about. The next issue is about cost and competitiveness. That's when the integrated and harmonization issues are much more important.