I think we are going more into a philosophical discussion about nationality and citizenship instead of sticking to his main question he wants to answer.
Lets wait to hear from the one who posed the question as to what his thoughts are after getting all the inputs. He knows the citizenship he has at the moment and can answer that question.
This particular issue has been discussed for years... I have been in Canada for 7 years and I have always heard this question over and over again... Should i put Russia or USSR? Should I put Ukraine or USSR etc.
It might seem to be philosophical, but it is not. It is very much a legal grey area... I wish IRCC clarified it on every form by a simple sentence like: "...for those of you who used to be a citizen of one country but that country ceased to exist blah blah blha..." A little instruction would help...
It does not only affect former USSR countries, if affects former Yugoslavia, it affects Germany before 1989 (not sure what it was exactly, but a very close friend of mine was born in the East Germany in a family of a Russian Soldier, but he had the same question over and over again until he became a citizen. Did he have German and USSR citizenships, or only 1? Or maybe 3 since his mother was Jewish? He still does not know the answer to that, since he was a baby, and whatever paperwork his parents got for him, he was stuck with that. And trust me, back in the day, you could be confused as hell with the bureaucracy that those soviet states had. The good news is he is now Canadian, and he did not get into any trouble by saying he was a Russian citizen all along).
The bottom line here is IRCC is at least aware of all this and SEEMS to be lenient towards mistakes made on these grounds, if those could be called mistakes at all. For one, I will be able to tell you how my application went if/when I get my Canadian citizenship.
So to sum it up, it is philosophical, but at the same time, this philosophy caused me many a sleepless night... I thought my PR was going to be rejected because of this (that's how paranoid I was
) And not only me...
Time will give us the answers... At the end, no citizenship will save you from the inevitable outcome we all share... Muahahah