If they nuke the moon, but it doesn't go off, surely this means NASA develops a US Space Navy and invades the moon 40 years later on charges of harbouring weapons of mass destruction?
It's hard to say. To deal with this, the Plowshare team proposed using "clean" nukes with low fission-fusion ratios, and burying the bombs deep enough that most of the fallout would be trapped by rock fallback.
Of course these nukes were not really clean. For a while there has been talk (and i wonder if they are trying to develop them) of Direct Fusion Bombs (H-bomb where you get fusion directly by using a strong conventional implosive instead of the old design where the implosive makes uranics fission which then provides the energy for fusion). If this kind of devices ever become real we will see a renewed discussion for using nukes for mega-engineering because they are (supposedly) much cleaner (no fissile products, no big neutron-activation).