Non-recognition of foreign governments

Cessation of diplomatic relations between states
Absence of diplomatic recognition
Abnormal diplomatic relations among states
Diplomatic restrictions
As a consequence of war or other incidents, states may cease diplomatic relations with each other. This may be initiated unilaterally. Subsequently such relations may only be partially restored, even after the signature of peace treaty following the termination of a state of war between them.
Although the USA and Vietnam signed a peace treaty in 1973, terminating the Vietnam War, little has been done in the intervening period to normalize relations between the two countries. In 1992, Mexico and the Vatican renewed diplomatic relations which had been formally broken in 1867. Since the establishment of the state of Israel in 1948, five Vatican popes have acknowledged Israel but never granted official recognition. Preparations for the establishment of full diplomatic relations began in 1992 and were scheduled to be completed in 1994.
(F) Fuzzy exceptional problems