It sure seems like a good idea: we've got all these intercontinental ballistic missiles lying around with nothing to do, under an hour from striking anywhere on Earth, plus a bunch of terrorists running around Afghanistan. So why not just use one against the other? The Air Force is thinking about doing just that.
Obviously, the Air Force isn't talking about nuking Afghanistan. Instead, they'd replace the nuclear warheads on ICBMs with conventional explosives, which would turn the ICBMs into a convenient global strike platform capable of destroying targets on the other side of the world in about 30 minutes. Sounds great!
The problem here, which you may have guessed by now, is that when someone launches an ICBM, it looks suspiciously like someone's launching an ICBM. Other nations who also have ICBMs (and some latent Cold War paranoia) probably wouldn't be a fan of this, especially considering that the quickest route from an ICBM launch site in California to the Middle East lies directly over Russia.
Last time I checked, the Russians generally get a little ornery when missiles which are usually equipped with a dozen nukes in the several hundred kiloton range (each) are tossed over their heads, and the U.S. saying "no, seriously, we're not aiming for you, honest" probably isn't going to fly. The other option might be using Trident ICBMs launched from submarines, but you run into the same problem, which is that an ICBM with a conventional payload heading from the pacific towards the Middle East looks just like an ICBM with a nuclear payload heading from the pacific towards China or North Korea.
The Air Force really, really wants the capability to strike anywhere in the world in under an hour, which is why they're so keen on the ballistic missile idea, despite what seems to be a major disadvantage, namely that launching ICBMs willy-nilly has the potential to start World War 3. Fortunately, they're also pursuing other, saner options, like strapping warheads to that Mach 20 hypersonic glider that they've been working on.
Via Danger Room