I can't find any backing, but it was probably a one-time waiver by the IIHF due to the fall of communism. There is plenty of confusion about things during that time with the defections and splitting of countries.
Nabokov was similiarly granted one, since although he was born in modern day Kazakhstan, his parents were native Russians, and he and them are Russian, not Kazakhstani. He appeared in one tournament for Kazakhstan before gaining the right to play for Russia.
IIHF would not be granting any special exemption to a player simply because he wanted to play at a higher level. Those are seemingly reserved for special cases like defections countries splitting. No way Kopitar, even if he got US Citizenship would ever play for USA.
Not true. If Kopitar wanted to play for USA he could. Here is the rule that allow him to do it:
Change of national eligibility (The ‘four-year’ case)
A player, who has previously participated in IIHF competition, can switch national eligibility (but only once in a player's life) if:
-He is a citizen of the new country of his choice
-He has participated for at least four consecutive years in the national competitions of his new country, during which period he has neither transferred to another country nor played ice hockey within any other country and has not played for his previous country in an IIHF competition during this four year period.
-He has an international transfer card (ITC) that shows the transfer to the national competition of his new country and which was approved and dated at least four years before the start of the IIHF competition in which he wishes to participate.
