Democide is a term coined by R. J. Rummel in his book "Death by Government". He defines democide as "the murder of any person or people by a government, including genocide, politicide, and mass murder". (Source: ).
Democide includes killings for political purposes (politicide), and large scale indiscriminate murder (e.g. the quota system that operated under Stalinism).
Democide is both a broader and a more restricted term than genocide. On the one hand, it includes killings on political or other grounds, which genocide (at least according to the original meaning of the term) does not. On the other hand, it excludes acts other than killing intended to destroy a ethnic or racial group, such as forced sterilization or the removal of children. Such acts count as genocide, but not democide.
According to research done by R.J. Rummel, the likelihood of a government committing what he calls democide, the mass killing by a government of its own population, correlates with the extent of governmental power. The more power a government has, the more likely it is to kill people, with wholesale killings being possible only in totalitarian regimes. Rummel also estimates that in the 20th century, 169 million people were killed in democide. Rummel's views have been criticized for not taking into context death caused by the absence of government by means such as anarchy, civil disorder, or foreign invasion.
Governments are not the only organizations that kill people. See homicidal organization.
Major cases of Democide
Sorted by approximate number killed. See also genocide for listing of genocides.
- Democide by Soviet communist government.
- Democides by Chinese communist government.
- Approximately 38 million people killed. 
- Nazi democide during World War II (1933-1945).
- Cambodia (1975-1979)
- 2.0 million people were killed during Pol Pot's rule 
- Groups that were target of democide:
- City dwellers
- Chinese (200 thousands)
- Vietnamese (150 thousands)
- Buddhist monks (40-60 thousands)
- Thai (12 thousands)
- People who had been exposed to Western ideas
- People who spoke a foreign language
- People who dealt with foreigners
- People who had an education
- Former government officials
- People who wore glasses
- Rwanda (April 1994)
- Roughly 800,000 Tutsis and moderate Hutus were killed by Hutus. See Rwanda/History.
- Armenian genocide by the Young Turk government (1915-1923)
- North America
- Lord Jeffrey Amherst is believed to have spread smallpox among Native Americans intentionally during the French and Indian War by distributing infected blankets. See http://www.nativeweb.org/pages/legal/amherst/lord_jeff.html.
- Indian Removal resulted in the death of many thousands of Native Americans.
- See Indian Massacres, Trail of Tears
-  Figures from R.J. Rummel, "Death by Government".
-  Figure from Britannica
-  Museum of Communism FAQ http://www.gmu.edu/departments/economics/bcaplan/museum/comfaq.htm
Good page about democide: http://www.hawaii.edu/powerkills/