Bright lines, however, have a way of fading, particularly when it comes to dedicated research programs. In 1983, President Reagan created the Strategic Defense Initiative, a program devoted to developing technologies that would protect the American homeland from nuclear attack. Despite large costs and widespread opposition from many of the nation's leading scientists, Reagan's initiative has survived for more than a quarter-century, focusing on different technologies and wrapping itself in different purposes. It has led the United States to withdraw from the Anti-Ballistic Missile Treaty in 2002, increased international tensions on numerous occasions, and siphoned money away from valuable uses toward technological fantasies. Large research initiatives can be tougher to kill than vampires: They feed fortunes, careers, and reputations. As with the Strategic Defense Initiative, a dedicated geoengineering research program risks creating a self-amplifying cycle of interest groups and lobbies, building momentum toward eventual deployment as a way of justifying the research.
Geoengineering is fraught with risk, but some technologies may have a place in our portfolio of responses. They will have to compete against renewable energy projects, conservation, adaptation programs, and other alternatives on the grounds of cost, feasibility, and moral and political acceptability. This amounts to abandoning the Promethean dream and entering the messy world of climate politics. We have created a problem of climate change and we must mobilize all of our resources in addressing it. But John Wayne is dead, and there is no Colt 45 peacemaker in sight.