It took futuristic technology to achieve one of the worst ecological disasters on record. Without such technology, after all, BP couldn’t have drilled the Deepwater Horizon well in the first place. Yet for those who remember their environmental history, the catastrophe in the gulf has a strangely old-fashioned feel, reminiscent of the events that led to the first Earth Day, four decades ago. And maybe, just maybe, the disaster will help reverse environmentalism’s long political slide — a slide largely caused by our very success in alleviating highly visible pollution. If so, there may be a small silver lining to...