[chm]

Colonizing Mars and "saving" Earth are not two opposed goals. You don't have to choose one or the other. You can do both. The problem I have with the argument proposed by McKay (and a lot of others) is that it's way too simplistic and misguided. It makes Mars colonization supporters like the ultimate pessimists, people who have already conceded the Earth battle to be lost. This is simply not true but it is implied by the argument.