Both Volokh and Bainbridge are off-base.
Problem #1: a high-end, $300 billion estimate of the cost of Kyoto should be taken with a boulder of salt. And $300 billion for Iraq is just the cost so far - I see no sign of it ending soon (not to mention the cost of increased oil prices due to decreased Iraqi oil production).
Problem #2: Kyoto's costs are offsets with benefits, while the Iraq wars costs don't come with benefits, but just with making us worse off.
We chose to go ahead with one of these options and not the other. Something makes me think we screwed up.