I think the search should be urgent. Even a billion for the most expensive option actual asteroid hunters are suggesting is small potatoes compared to the potential costs of even a small impactor striking a major city. Mitigation methods are another matter ranging from the cheap to the impossible with current technology. I think we should fund the recommended search with additional money for NASA and a relatively inexpensive test mission like a gravity tractor of use for the more frequent small impactors. An inexpensive small nuke test might be nice as well, but is probably politically infeasible without a serious threat identified.

While my interest in colonizing space stems in part from a eggs out of one basket preference, and agree a real threat might push us forward, the technical incompetence of our political system leaves me with no desire to face a real impact threat in the near term.

Regards,
Mark