Um - read much? I said the black market, not the Russian goverment. Russia make the best RF jammers in the world, bar none.
They would make a counter for such swarms and if there were demand from other militaries, sell them. Some of those would find there way to the balck market and to the US, provided they were small and hand held. So much for swarms.
Without getting into detail there are 2 separate issues to discuss neither of which would be appropriate in this forum.
#1 Airspace Control / management / Air Superiority Etc. etc
#2. Radio Frequency Control / management / communication security