Conventional warheads on SLBMs?

As reported in William Arkin's Washington Post blog, the US Navy is going to be developing a conventional (that is, non-nuclear) warhead for the Trident ballistic missile submarine fleet:

Secretary of Defense Donald Rumsfeld has given the Navy go ahead to develop a conventionally armed Trident missile. Two dozen existing nuclear-armed submarine-launched missiles will be converted to carry conventional warheads. The missiles will then be assigned "global strike" missions to allow quicker preemptive attacks.

For the first time since intercontinental ballistic missiles were "captured" in arms control treaties 40 years ago as unique and potentially destabilizing weapons, the United States will muddy the waters by modifying an existing nuclear weapon for use in day-to-day warfare.

The conversion of Trident missiles abandons the strict segregation of nuclear from conventional weapons.

As a few folks have already pointed out, this would be a very quick way of inducing organizational colonic spasms in the high commands of the Chinese and Russian defence forces, with potentially cataclysmic results. Launching a ballistic missile is a particularly bad idea in an already trigger-happy area of the world.

On a cost-basis, it doesn't make a lot of sense either, as sending an F/A-18 on a strike mission would be cheaper and less likely to result in "accidental" launches from Russian or Chinese subs/silos.

Arkin thinks that the reason for the development is less military and more military-industrial complex:

So isn't it ironic that Donald Rumsfeld, the prophet of military transformation and the booster of an effects based approach is releasing a half a billion dollars to develop a provocative weapon that falls back on the old paradigm?

The reason is that Donald Rumsfeld is a weakling. For all his huffing and puffing, he can't say no to either the military or the defense contractors.