This is assuming that all regulations are the same though. The Richard Nixon administration made the environment a policy priority in 1969-1971 and created two new agencies, the Council on Environmental Quality (CEQ) and EPA. The Clean Air Act was a Republican bill, and was dealing with things like carbon monoxide, particulate matter, and sulfur dioxide. It is the changing nature of the agency that made Republicans lose faith in it. Like how Republicans can like the idea of the United States Department of Veterans Affairs, but after seeing scandal after scandal want the VA scaled back or their responsibilities shifted to other departments who still have their confidence.