Most countries, military establishments, and official religions maintain a careful silence concerning periods or incidents in the past when they have engaged in repressive or otherwise morally repugnant actions against some group. This leads to pressure to avoid mention of such events in history textbooks or other media. Examples include treatment of prisoners of war and wartime atrocities, forms of dirty war and use of death squads, as well as failures to respond to requests for assistance in emergencies.
After the replacement of the military regime in Argentinia in 1990, the president pardoned military leaders for the crimes they had authorized or committed during the dictatorship. The authorities have since then actively discouraged public discussion of the events.