There is no question, the Americans have the right to examine every single person seeking to enter the US, and to undertake whatever measures US law permits.

I think it is important for us to distinguish between naturalized Canadian citizens who were born in these countries, and nationals of these countries who are here with (or without) other status.

A naturalized Canadian citizen has been screened twice--once in connection with permanent residence, and once in connection with citizenship. This places the person in a considerably different risk profile than a person who is a refugee claimant or a temporary worker.

With respect to security screening, Canada and the US share enormous amounts of intelligence related to screening. Although the Americans make a lot of noise about security, the fact of the matter is that we are generally better at it (if only because we have a smaller pool to clear).

The "generosity" of our system that so many critics decry actually provides us with a lot more security. With no disincentive to come forward, we know a lot more about who is inside our borders. The Americans are faced with 8 million people that the INS has never seen and don't know.

Ironically, the one solid example of a Canadian source threat to the US would not be caught under this screening. Ressam was masquerading as a Canadian-born citizen, and he is Algerian.