Communists are conspirators against the Supreme Law of the Land. They belong nowhere, but least of all in the United States. Any civilian communist should be allowed to leave with understanding that they may not own property in the US, hold citizenship in US, reside in US, re-enter US, or ever influence poltics in US ever again. (By the way, communists would not extend the same allowances for principled people anywhere) Any violation of those terms should mean they join the treasonous officials feeding the Tree of Liberty.