What is the theme of "embassy" by W.H. Auden?

Embassy

As evening fell the day’s oppression lifted:
Far peaks came into focus; it had rained:
Across wide lawns and cultured flowers drifted
The conversation of the highly trained.

Two gardeners watched them pass and priced their shoes:
A chauffeur waited, reading in the drive,
For them to finish their exchange of views;
It seemed a picture of the private life.

Far off, no matter what good they intended,
The armies waited for a verbal error
With all the instruments for causing pain:

And on the issue of their charm depended
A land laid waste, with all its young men slain,
Its women weeping, and its towns in terror.