In Part 2, John Grady and Rawlins discuss Alejandra. Rawlins makes a few ironic assumptions about Alejandra and John Grady's possible relationship, exposing how differently he and John Grady think about love:
How old is she?
Seventeen.
Rawlins nodded.
What kind of a school is it she goes to?
I dont know. It’s some kind of a prep school or somethin.
Fancy sort of school.
Yeah. Fancy sort of school.
Rawlins smoked. Well, he said. She’s a fancy sort of girl.
No she aint […]
This one of course she probably dates guys got their own airplanes let alone cars.
You’re probably right […]
What’s her name? said Rawlins in the darkness.
Alejandra. Her name is Alejandra.
Even though Rawlins insists that Alejandra would never date John Grady because he isn’t “fancy” enough, it appears he is completely wrong. Alejandra does not have the values Rawlins assumes she does. He misjudges Alejandra, only understanding her beauty and unattainability—he doesn't even remember her name.
In this case, even though he takes the position of lecturing John Grady, Rawlins is portrayed as immature while John Grady is wiser. His deep care for Alejandra, though, turns out to be nearly as foolish as Rawlins’s shallow assessment of her: love will not be enough to keep John Grady and Alejandra together. Both boys, even though they might believe they fully understand romance, still have a lot to learn.
In Part 3, the Captain and his assistant murder Blevins. The novel highlights the ironic contrast between this disturbing killing and Blevinss' youthful demeanor to underscore the senseless brutality of this action:
Rawlins looked at John Grady. His mouth was tight. John Grady watched the small ragged figure vanish limping among the trees with his keepers. There seemed insufficient substance to him to be the object of men’s wrath. There seemed nothing about him sufficient to fuel any enterprise at all.
This is an example of situational irony. Blevins’s youth and vulnerability (he is described as a "small ragged figure") is contrasted with his harsh, execution-style killing in the passage, highlighting the complete depravity of the event. Violence out in the country seems to not only refuse to spare innocence, but to target it specifically. Blevins is not killed in spite of his age, but because of it.
This is a difficult reality for the older boys to face, especially because it runs counter to their romantic understanding of morality. The Captain, who ostensibly carries out justice, entirely upends their understanding of how authority ought to work. The irony of Blevins' death exposes the imperfect and often ruthless nature of justice in the border country.
When John Grady, Rawlins, and Blevins first encounter the Captain in Part 3, the Captain delivers an ultimatum that is an example of situational irony:
You have the opportunity to tell the truth here. Here. In three days you will go to Saltillo and then you will no have this opportunity. It will be gone. Then the truth will be in other hands. You see. We can make the truth here. Or we can lose it. But when you leave here it will be too late. Too late for truth. Then you will be in the hands of other parties. Who can say what the truth will be then?
This is an ironic statement because a police interrogation is supposed to hold finding truth as its goal, but the Captain reveals that he is just as satisfied to spin his own story. Real truth makes no difference to him—he merely cares about claiming to have found the truth. The impact on his prisoners means nothing to him, nor does uncovering the real events that led them there. Any romantic ideals of justice John Grady still held are completely shattered here, and the boys realize that they cannot count on adults or authority figures to act justly.