The Foxholes of Mars
The wars of the far future will be fought with giant spaceships, but it will still take the infantryman in the mud to hold down the planets.

War never changes. Men fight men with rocks and spears then with arrows and cannon. Future men will fight with advanced weapons like space ships, vibration rays, cobalt bombs and robots but they will still fight. In the end, after the space battles have ended, it will still require the grunts, whether in the shape of men or Martians or bugs or jellyfish, to hold the planets. Beings in the mud of a thousand worlds, beings used like fodder to actually hold what is being contested. The beings in foxholes. And these beings will become just as bitter and angry and hateful in the future as they have become in all of the past. They will be dangerous.