A condition of not having an authority who can enforce rules on all actors. The International System in the 21st century is usually considered an Anarchy.
A group of alliances which require all members to declare war against the attacking party. The system of alliances which led to World War I through the Balkan Powder Keg are an example.
A chicken game is a situation where two states engage in brinkmanship even though the ideal solution is for one state to yield to the other. For example, the United States and the USSR risked global nuclear war to protect relatively minor strategic interests during the Cuban Missile Crisis.
a Prisoner's dilemma is a situation where two states act in seemingly irrational ways due to their inability to make binding promises in the international system. For example, two rivals states might built up their respective military's even if neither wants to invade the other.
The expression of a common sense of identity and purpose combined with the creation and implementation of institutions that express a particular identity and shape collective action within a geographical region.
When states prohibit their citizens from trading with or traveling to a target country in order to punish it or deter it without the use of military force.
A situation in international relations where a states decision to increase its security by expanding its military causes other states to do the same to protect their security interests creating a vicious cycle.
A state that seeks to maintain the status quo the international system, in contrast to a revisionist state. For example, the United States in the contemporary international system.