At the beginning of the story, these three men are talking about the war that is just ending. They are talking about it in slightly different ways.
Swift is saying how weird it will have the war be done -- he has gotten used to war so it will feel wrong not to be at war with Deneb.
Henderson is happier, or more relieved. He is so glad that human beings no longer have to worry about the mass destruction of their race.
Jablonsky is more bitter. He is unhappy because the people are giving Multivac the credit for winning the war.