It's not just expense; due to nuclear early-warning systems mostly being keyed off ICBM launches, it's risky to launch one. You're gambling that other nuclear-armed powers will believe you that it's conventionally-armed and not heading at them, which is a decision they only have several minutes to make. So in practice ICBMs have usually not been considered a normal part of the conventional-force arsenal.

>You're gambling that other nuclear-armed powers will believe you that it's conventionally-armed and not heading at them

yep, and when this http://www.panoramio.com/photo/13572904 sees such a highly maneuverable vehicle flying 20 Machs over Europe you don't think it would cause questions that must be answered during next few minutes? At least in case of ICBM it is clear where it flies to once it launched.

I think it is pretty funny that our country is trillions of dollars in debt and here our military is making toy FN planes that cost 125 million dollars. What the f is wrong with this picture!