The Frozen Planet

It is rather unusual, Magnan said, to assign an officer of your rank to courier duty, but this is an unusual mission.
Retief sat relaxed and said nothing. Just before the silence grew awkward, Magnan went on.
There are four planets in the group, he said. Two double planets, all rather close to an unimportant star listed as DRI-G 33987. They're called Jorgensen's Worlds, and in themselves are of no importance whatever. However, they lie deep in the sector into which the Soetti have been penetrating.
Now— Magnan leaned forward and lowered his voice— we have learned that the Soetti plan a bold step forward. Since they've met no opposition so far in their infiltration of Terrestrial space, they intend to seize Jorgensen's Worlds by force.
Magnan leaned back, waiting for Retief's reaction. Retief drew carefully on his cigar and looked at Magnan. Magnan frowned.
This is open aggression, Retief, he said, in case I haven't made myself clear. Aggression on Terrestrial-occupied territory by an alien species. Obviously, we can't allow it.
Magnan drew a large folder from his desk.
A show of resistance at this point is necessary. Unfortunately, Jorgensen's Worlds are technologically undeveloped areas. They're farmers or traders. Their industry is limited to a minor role in their economy—enough to support the merchant fleet, no more. The war potential, by conventional standards, is nil.
Magnan tapped the folder before him.
I have here, he said solemnly, information which will change that picture completely. He leaned back and blinked at Retief.
All right, Mr. Councillor, Retief said. I'll play along; what's in the folder?
Magnan spread his fingers, folded one down.