Abstract
It is now generally recognized that Earth is at risk of a devastating collision with an asteroid or a comet. Impressive strides in our understanding of this threat have been made in recent decades, and various efforts to deal with it have been undertaken. However, the pace of government action hasn’t kept up with the advance of our knowledge. Despite the daunting dimensions of planetary defense, one intrepid NGO has stepped up to the plate: The B612 Foundation has embarked on a half-billion-dollar project, called Sentinel, to map the estimated one million near-Earth objects that could wipe out a city or even end civilization. This article offers an explanation of how it came to be that private citizens have assumed what is arguably government’s primary mandate to "provide for the common defence." It then examines some of the practical – or, if you will, ethical – risks that may be attendant on such a shift of responsibility. Finally, a new policy emphasis is proposed.