The short story "An Act of Vengeance" by Isabel Allende tells of an unlikely love between a savage, ruthless man and the woman he raped when she was a young girl. The motivation for the savagery of Tadeo Cespedes has to do with the politics of the unnamed country in the story, specifically the civil war that is taking place in the beginning.

Dulce Rosa Orellano is the daughter of Senator Orellano, "the most powerful man in the entire province." He is so powerful, in fact, that his daughter Dulce wins a contest and becomes Carnival Queen, even though many people say that she was not the most beautiful woman there.

Allende presents Tadeo Cespedes as being zealously devoted to the Civil War, so much so that

during all his twenty-five years he had neither had time to learn poetry nor to look at women.

[...]

Ever since he had begun to shave he had had a weapon in his hands, and he had lived for a long time amidst the sound of exploding gunpowder. He had forgotten his mother's kisses and even the songs of mass.

In other words, Tadeo is a fanatic. He is "habituated to violence," and he has been fighting this civil war for a long time. The struggle is all he knows.

The specific circumstance that causes Tadeo to attack the home of Senator Orellano is a presidential election in which his party wins. After so many years of living and fighting clandestinely, his party wins the election, and he is a man of power.

Tadeo's last act as a revolutionary is "the punitive expedition against Santa Teresa," the town in which Dulce Rosa and her father the Senator live. His intention is "to teach everyone a lesson and eliminate the leaders of the opposition." This is the reason why Tadeo and his men attack the Orellano house, and it is why Senator Orellano tries to safeguard his daughter and fight to the death with his servants.

He knows that Tadeo is coming not to arrest him, but to kill him, and that the attacking men will dishonor his daughter as well. At the end of the attack, it is Senator Orellano's intention to shoot his daughter rather than let her to be captured and raped by Tadeo and his men. However, she persuades him to allow her to live so that she can carry out an act of vengeance on Tadeo.