Hakio wrote:"What's wrong with planetoids?" Sia asks defensively. "I like planetoids. Asteroids and dwarf planets. Cool shit."
Nothing wrong per se, Ms. Hedishi, but you may be artificially limiting (not to say castrating or shooting yourself in the foot) your resolution by insisting on including the term. A slightly different approach that might work better would be to define something like "planetary object" as "anything sufficiently massive to be rounded by its own gravity;" then outlaw the destruction of 1) any inhabited planetary object, and 2) any uninhabited planetary object whose remnants or debris would then threaten a civilian population; except for self defense where a collision of planetary objects is imminent. Perhaps throw in a strongly urge that currently uninhabited but easily inhabitable planetary objects not be used as targets of planetkiller weapons, either for testing or for resource extraction - but that's not strictly necessary here.
This would leave a WA member civilization able to destroy, or avert by surface ablation, any significant threat to itself, while still outlawing use of planetkillers against enemy planets, large asteroids, moons, and other (yes) planetoids.
As to nuclear weapons, you may just have to bite the bullet and put in a CLARIFIES that this resolution totally ignores weapons incapable of causing mass extinctions without mass detonations, including nuclear (fission) and thermonuclear (fusion) weapons. That's clunky, but you know someone would say Hey, nukes can cause mass extinction if you set enough of 'em off, so obviously you're targeting my nuclear arsenal in violation of like four or five other resolutions!
Hope this is helpful.