Space based kinetic strategic weapons

For quite some time, science fiction writers have speculated that folks living in space (usually on the moon) could control Earth because of the threat that it would be trivially easy for them to drop "rocks" on cities, causing enormous destruction. A variation on this theme explains why dominance in space is important to our freedom and way of life. Weapons of this nature have their problems, but they are probably much harder to detect & defeat than conventional missiles. By the time you see the glowing dot coming at you, it is probably too late to block it or leave the area.

Rods from God | Popular Science:
"A pair of satellites orbiting several hundred miles above the Earth would serve as a weapons system. One functions as the targeting and communications platform while the other carries numerous tungsten rods—up to 20 feet in length and a foot in diameter—that it can drop on targets with less than 15 minutes’ notice. When instructed from the ground, the targeting satellite commands its partner to drop one of its darts. The guided rods enter the atmosphere, protected by a thermal coating, traveling at 36,000 feet per second—comparable to the speed of a meteor. The result: complete devastation of the target, even if it’s buried deep underground.
. . .
The concept of kinetic-energy weapons has been around ever since the RAND Corporation proposed placing rods on the tips of ICBMs in the 1950s; the satellite twist was popularized by sci-fi writer Jerry Pournelle. Though the Pentagon won’t say how far along the research is, or even confirm that any efforts are underway, the concept persists. The “U.S. Air Force Transformation Flight Plan,” published by the Air Force in November 2003, references “hypervelocity rod bundles” in its outline of future space-based weapons . . .

Launching heavy tungsten rods into space will require substantially cheaper rocket technology than we have today. But there are numerous other obstacles to making such a system work. Pike, of GlobalSecurity.org, argues that the rods’ speed would be so high that they would vaporize on impact, before the rods could penetrate the surface. Furthermore, the “absentee ratio”—the fact that orbiting satellites circle the Earth every 100 minutes and so at any given time might be far from the desired target—would be prohibitive. A better solution, Pike argues, is to pursue the original concept: Place the rods atop intercontinental ballistic missiles, which would slow down enough during the downward part of their trajectory to avoid vaporizing on impact. ICBMs would also be less expensive and, since they’re stationed on Earth, would take less time to reach their targets."

The designers of these weapons understand these arguments - it would be interesting to hear their counters to them. Certainly multiple satellites can reduce the absentee ratio, and possibly small boosters could be used to place the rods where needed. NASA has learned a lot about slowing vehicles on reentry - some of this knowledge might be transferable at a reasonable cost. at the very least, it keeps our enemies busy designing counter-measures rather than offensive weapons.