On Sept. 29, European parliamentarians adopted a resolution calling for next June's United Nations Conference on Sustainable Development in Rio de Janeiro to demand that all nations adhere to the "principle of non-regression." In a nutshell, the claim is that international law forbids nations to amend or repeal laws designed to protect the environment. . . . There's no mystery why the principle of non-regression is so appealing to many environmentalists. It would exempt existing environmental regulations from review, reform and repeal, even if the costs have proven to be greater than the benefits. The mystery is why the parliament of an economically struggling continent would agree.U.S. environmentalists also insist on policies with huge economic costs without environmental benefits as evidenced by the efforts to stop the Keystone pipeline. Must we follow Europe’s failed economic policies and its environmental nonsense, too?