In Chapter 6, Maria and Jordan exchange words in a conversation that is both amusing and revealing. The excerpt speaks to Maria and Jordan's different cultural and political contexts, establishing them as coming from different worlds. Hemingway employs dramatic irony to draw out this interaction:
"My father was a Republican all his life," Maria said. "It was for that they shot him."
"My father was also a Republican all his life. Also my grandfather," Robert Jordan said.
"In what country?"
"The United States."
"Did they shoot them?" the woman asked.
"Qué va," Maria said. "The United States is a country of Republicans. They don't shoot you for being a Republican there. "
This passage contains both direct statements and connotations that readers will pick up on, but that the characters (Maria, at least) are unaware of. American Republicans at the time were quite different from Spanish Republicans, who were far left-leaning (even communist; nicknamed the "Reds" or Rojos by their opponents). While McCarthyism (persecution of communists) would not gain steam in the U.S. until the 1950s/60s, the Republicans of 1930s America were certainly not far left-wing.
Hemingway utilizes dramatic irony in this passage to establish Maria and Jordan's differences. In spite of these differences, the two characters are inextricably drawn to one another.
In the following excerpt from Chapter 18, Jordan recounts a conversation he had with Karkov in a flashback sequence. The content of this conversation is situationally ironic, indicating the at times confusing and contradictory attitudes characters have towards violence.
"But I have a little more here," Karkov had grinned and showed the lapel of his jacket. "You simply put the lapel in your mouth like this and bite it and swallow."
"That's much better," Robert Jordan had said.
"Tell me, does it smell like bitter almonds the way it always does in detective stories?"
"I don't know," Karkov said delightedly. "I have never smelled it. Should we break a little tube and smell it?"
In the above instance of situational irony, Karkov and Jordan discuss the act of poisoning oneself if captured by opposing forces. Karkov responds differently to this conversation than one might expect from the situation, speaking "delightedly" at the prospect of smelling poison. Jordan, too, is no bystander: he displays a morbid curiosity about the scent and use of poison, citing detective stories as his principal information source. Given the serious tone afforded violent topics in the novel, this passage stands out as incongruous. Both characters, for the moment, are not according death and destruction the consideration they deserve.