A power vacuum is a condition that exists when someone has lost control of something and no one has replaced them. It is usually a political situation that can occur when a government has no identifiable central authority. In a power vacuum, much like a physical vacuum, other forces will tend to "rush in" to fill the vacuum as soon as it is created, perhaps in the form of an armed militia or insurgents, military coup, warlord or dictator.
"The strength of the barriers in eastern and south-western Europe varied from century to century. The nomads' worlds rotated between these areas of negligence, weakness and sometimes ineffectual vigilance. A physical law drew them now westwards, now eastwards, according to whether their explosive life would ignite more easily in Europe, Islam, India or China. Eduard Fueter's classic work drew attention to a cyclonic zone, an enormous vacuum in 1494 over the fragmented Italy of princes and urban republics. All Europe was attracted towards this storm-creating area of low pressure. In the same way hurricanes persistently blew the people of the steppes eastwards or westwards according to the lines of least resistance.
During or following a civil war there is often a power vacuum of some sort. For example, the war-torn nation of Somalia is currently mired in a power vacuum, with no central government or president exercising control over the supposed "Republic of Somalia".
The start of civil war in Bosnia in 1992 was marked with a power vacuum following disintegration of Yugoslavia.
After the Second World War, there was a power vacuum in Europe. Along with the division of East and West Germany, Stalin's diplomacy and governance, the development of the atomic bomb, policies of containment of communism, the expansionism of the USSR and USA and a growing lack of trust (fear of a hegemony) were seen to be factors in the emergence of the Cold War.
More recently, the tight control which Saddam Hussein's Baath party exerted on Iraq could have been exploited during a transitional hand-over period following the 2003 invasion of Iraq. Instead, the US Government's policy of purging Baath party members from the Iraqi government after the invasion created a power vacuum which was quickly filled by insurgents, who then began to attack American service personnel using improvised explosive devices and snipers.
- Fernand Braudel, Capitalism and Material Life, New York, Harper & Row, 1967, vol. I, p.57