Q: What does “state failure” mean?
A: A state that is failing has several attributes. One of the most common is the loss of physical control of its territory or a monopoly on the legitimate use of force. Other attributes of state failure include the erosion of legitimate authority to make collective decisions, an inability to provide reasonable public services, and the inability to interact with other states as a full member of the international community. The 12 indicators cover a wide range of elements of the risk of state failure, such as extensive corruption and criminal behavior, inability to collect taxes or otherwise draw on citizen support, large-scale involuntary dislocation of the population, sharp economic decline, group-based inequality, institutionalized persecution or discrimination, severe demographic pressures, brain drain, and environmental decay. States can fail at varying rates through explosion, implosion, erosion, or invasion over different time periods.
— The Failed States Index 2007: FAQ and Methodology