Suppose we were (as we might be) an influence, an idea, a...

Suppose we were (as we might be) an influence, an idea, a thing intangible, invulnerable, without front or back, drifting about like a gas? Armies were like plants, immobile, firm-rooted, nourished through long stems to the head. We might be a vapour, blowing where we listed Ours should be a war of detachment. We were to contain the enemy by the silent threat of a vast, unknown desert