US foreign policy is a big reason why only authoritarian communist governments have been able to survive.

Nicaragua is a great example of this. The Sadinistas lost power through free elections in which the US interferred. Now that the Sadinistas are back in power, the freedom of their elections has been rapidly decreasing.

"Communist" as a lable has been so misused and unclearly defined for so long that it is mostly useless as a descriptive term.