Since the end of the Argentinean military dictatorship (euphemistically called "National Reorganization Process") and the Dirty War, when guerrilla groups (mainly left-wing Peronist Montoneros and the Marxist-Leninist Ejército Revolucionario del Pueblo or ERP) were persecuted by the armed forces (together with law enforcement agencies and paramilitary groups), this term has been in wide use by people mainly in human rights movements, the political left, and former guerrilla members and supporters.
The term "theory of the two demons" is used pejoratively in left-wing discourse, and is attached to public personalities who plead to support "national reconciliation", sometimes appealing to the Christian idea of "forgive and forget", while (allegedly) having ulterior intentions.
Since the image of the military has been tarnished by human rights abuses, economic chaos and the Falklands War defeat, accusers claim that advocates of right-wing repression must resort to reconciliation rhetoric, because a plain admission of support would disqualify them in the eyes of most Argentines.
Yet, Montoneros killed notable persons who were not guilty of violence against the people (such as Arturo Mor Roig, the architect of the 1973 democratic transition, labor union leader José Ignacio Rucci.
Moreover, Argentine state terrorism included the illegal arrest and disappearance of high-school students asking for a rebate in public transportation, nuns who assisted the poor, and persons who happened to be on a guerrilla's telephone list.
When its report was delivered to the government, the Interior Minister, Antonio Tróccoli, gave a speech equating Dirty War criminals and terrorists that was criticized by the leftist and Peronist opposition as an exponent of the "doctrine of the two demons".
After taking office in 2003, the Néstor Kirchner administration shifted the focus towards the uncovering and punishment of crimes of the Dirty War, including those formerly covered by the now-repealed amnesty laws passed in the mid-1980s.
Journalist Magdalena Ruiz Guiñazú, a former member of CONADEP, criticized the new prologue: "It is a grave historical mistake to think that the report was an apology of the theory of the two demons."