Diplomatic analysts sometimes talk of tinderboxes and sparks. A tinderbox is a state that only just manages to continue in its present situation, usually either because its economy is too weak to support the demands placed upon it or because its political system is only just coping with the stresses it faces, or both.  

Such states can continue for some time, but they are vulnerable to sparks — to events, usually unforeseen, that suddenly topple a political structure. The effect is often dramatic. States that may have appeared outwardly stable for a long time suddenly vanish or are plunged into chaos.