Hesayne was named bishop of Viedma, about 800 kilometres southeast of the capital in 1975. When the military junta took power in a coup the following March, Hesayne was quick to denounce the kidnappings and persecutions that being perpetrated by the regime when evidence of foul play began to emerge.
TORTURE IS 'IMMORAL'
"Torture is immoral [...] it is violence and the violence runs counter to humanity and to Christianity," he stated publicly in an interview, after talking with the notorious general Albano Harguindeguy, then-interior minister.
In 1985, after the return of democracy to Argentina, Hesayne gave his testimony in the famous Trial of the Juntas, which saw leaders like Jorge Videla and Emilio Massera, among others, sentenced to jail time for their crimes against humantiy.
Years later in 2006, after the overturning of the amnesty laws that had protected former military dictatorship officials from prosecution, he gave testimony in court about the death of fellow bishop Enrique Angelelli, from La Roja, who died in 1976. He was described by Hesayne as a "martyr."
The La Roja bishop, beautified last March, died in 1976 in a transit incident that the dictatorship claimed was an accident. But, three years later, the Judiciary acknowledged the act as orchestrated by the junta, a ruling largely supported by Hesayne's testimony.
He recounted how Angelelli had been saying that he was consistently persecuted and that he planned to retire because he was worried his congregation would be harmed as a result. A few days after Angelelli's death, Hesayne said he received an anonymous letter with Córdoba stamps directing him to "stop talking, we've already quieted Angelleli."
Hesayne also famously denounced the long term "neoliberal economic policies" of Carlos Menem. He defended the necessity of heads of Church to continue participating in politics.
In keeping with his belief that members of the Church should remain involved in politics, the bishop often voiced his opinions to heads of state through handwritten letters.
He wrote to Menem in the midst of a debate about the rate of poverty in the country. "You can even deceive the Pope with your political fallacies, but not Jesus Christ, who knows there's too much poverty now."
Along those same lines, he wrote to Fernando de la Rúa calling his economic policies "genocide of the white glove."
Later, he addressed Eduardo Duhalde in a letter. "It will be 26 years that I will come hearing the promise that, once finances are arranged and payments of the State's debt have been made, the solutions to social problems can be discussed."
Hesayne's career was marked by a commitment to the social pact and to work in the area of human rights, even when it put him against many members of the hierarchy of the Catholic Church.
At 72-years-old, in 1995, he resigned from his post and dedicated himself to layperson training in Azul.