I think that what a Canadian official might have asked is that the applicant provide a proof that he had declared in front of a U.S. immigration official that he does not intend to reside in the U.S., at which point the U.S. official would pronounce that the person has given up their U.S. residency and start the process to cancel it.
I.e. Canadian migration authorities cannot take away a U.S. permanent residency but may try to indirectly force an appilcant to give it up, by conditioning thir Canadian citizenship upon this. I don't believe this is within the present or incoming law, but it's understandable that they may do it.
What do you guys think?
