If certain conditions are met the child of a foreign adoption enters the US on a special visa which grants citizenship as soon as they (he in our case) touch American soil. No additional action is required of the adopting parent(s) ... the Certificate of Citizenship arrives automatically a few weeks later.
I did not know that.
With Russian adoptions, the child maintains dual citizenship until he is an adult. When the child reaches adult age, he or she then has to relinquish the dual citizenship if they want. This is part of Russia’s policy for their adoptions - not the U.S.’s.