Miller McCune: The environmental movement has been pushed forward since its inception by catastrophes like the oil spill now spreading in the Gulf Mexico. The 1969 blowout off the coast of Santa Barbara helped spur the creation of the first Earth Day and, not long after, the Environmental Protection Agency. By the time the Exxon Valdez tanker started spewing oil in 1989 off the coast of Alaska, a grassroots movement had grown into a political force, some groups with Washington offices and lobbyists …