WMDs

John makes some good points (and in a relatively restrained manner,
bravo!) (yes, John, you can mutter imprecations about my lineage
quietly... *grin*). 

Two points:

MAD depends on a balance of symetric threat. Fighting NGOs is tougher,
because they aren't as identifiable and the threat is asymetric. WMDs
are more likely to be deployed by these agencies and by fanatics, which
also means that most gov'ts will work hard to prevent this (SIGINT,
IMINT, HUMINT, covert and overt ops, diplomacy, hearts and minds stuff).

The ultimate bombardment tactic if you have a year or two to spare is
winding up some stealth coated rocks to a good speed. Planets (and
bases) dodge poorly. No power signature, maybe not much of a radar
signature if coated with signal absorbent material. And the launching
party can be a year gone.... 

But since this doesn't go one, even though any Belter could do this, we
have to assume that:
1) Lots of less obvious monitoring/counteractivity going on
2) Good sensors and PDS nets for planetary regions of high value

Otherwise, 2183 would feature a lot of dead worlds. 

I mean, before the Kra'Vak arrive and start cleaning up the Hu'man
infestation. (Drat, there are those darned apostrophes again.... feeble
Hu'man vocal apparatus.....)