On the intergovernmental agreement and the enhanced exchange of tax information on the Canada-U.S. tax convention, the point of that, in my understanding, is to avoid double taxation, if you will. You pay the appropriate taxes in the appropriate country and you back that fact up: that can be based on citizenship. But citizenship comes with a whole realm of responsibilities. Quite frankly, if you hold American citizenship, you have to pay American taxes.
Again, most of the folks in my part of the world have American passports. They may be permanent residents living in Canada, but they still travel on American passports. They hold investments and some still own property in the U.S. They're Canadian citizens or permanent residents because they live in Canada and they have no intention of returning to the U.S., but they still have ties.
That leads to my question and the very difficult decision that some individuals may have to make. If they really don't want to pay taxes in the U.S., then they would have no choice, I would expect, but to renounce that American citizenship and the benefits that come with it. If they do that, is there a liability up and to the point that they do that?