The "Rods" are a decendent of the "Thor's Hammer " idea proposed in the 80's as part of the 'High Frontier" initiative. It got together a bunch of Sci Fi types (RAH and Jerry Pournelle among them) retired military types and policy wonks. It proposed putting bundles of dense metal rods in polar orbits equiped with various sensors. On command the rods would deorbit, and become what amounted to a guided meteor shower. Apparantly the military is finally moving on this idea.
It could be used against fixed targets, armour, airfields, naval units, you name it.