I find it hard to believe that it’s still necessary to make the argument that “nuclear weapons are bad”, but apparently half the country still hasn’t gotten the memo. Worthwhile reading is this Harper’s essay discussing why a nuclear earth penetrator is neither clean nor efffective.
[A] 400-ton explosion would have to occur a full 600 meters underground in order to be “contained.” These guidelines also stipulate a carefully sealed burial shaft to contain the blast, not a maw. Even the B61-11, at its current, inadequate impact speeds, does not burrow a clean rabbit-hole in the ground but rather kicks up a crater like a meteorite; any faster-moving penetrator would do so to a still greater degree.
Even supposing that the missile’s point of entry were miraculously neat, a nuclear blast at the depths a real missile could attain would invariably breach the surface of the earth, expelling a hot fallout cloud in what is known as a “base surge.” Base surges are more dangerous than traditional fallout clouds because they are more toxic, containing irradiated particles of dirt and rock. They also spread more quickly, sweeping across the surface of the earth in every direction, outward rather than upward. Bunkers are usually built in urban areas, so many thousands of deaths would be a virtual certainty. Even a 1-kiloton bunker buster–a relative firecracker, with a tiny fraction of the explosive power of the high-yield RNEP–detonated at fifty feet underground could eject about 1,000,000 cubic meters of radioactive soil.