 What is the role of the Saarkkadic people in this story?
To violate the rigid social setup of Saarkkad would mean the instant closing off of the supply of biochemical products that the Saarkkadic laboratories produced from native plants and animals—products that were vitally necessary to Earth's war, and which could be duplicated nowhere else in the known universe. The Karna pointed out that the Saarkkad sun was just as far from Karn as it was from Earth, that it was only a few million miles from a planet which was allied with Earth, and that it was unfair for Earth to take so much time in preparing for an armistice. It wouldn't have been a problem at all if Earth and Karn had fostered the only two intelligent races in the galaxy.
 They produce some materials important to the Terrans.
 The other races are vying for attention from them for support in the war  They are overseeing the peace talks.  They produce some materials important to the Terrans.  They provide a place for Malloy to hide from his own people.