US Immigration: "No Commies"

 The only problem here is the classic one:  closing the barn door a little too late.

“On Oct. 2, USCIS issued policy guidance in the USCIS Policy Manual to address inadmissibility based on membership in or affiliation with the Communist Party or any other totalitarian party. Membership in or affiliation with the Communist Party or any other totalitarian party is inconsistent and incompatible with the Naturalization Oath of Allegiance to the United States of America, which includes pledging to “support and defend the Constitution and laws of the United States.”  --quoted at National Pulse

There are lots of Commies present in the US.  Can we push them back into the sea?