They are more than looking the other way, They are active perpetrators of a hoax on the public. This is not a crime.
Never. Treason by civilians is tried in Article III courts. Armed forces under UCMJ are charged with a different crime and tried by a military tribunal.
ex parte Milligan
Only a few treason cases in all of US history. Tokyo Rose (later pardoned) is one of them.
Brexit indeed in peril. Boris Johnson intends to rejoin the EU. He's just looking for cover, etc.