Many nations are now pursuing a policy of 'sustainable development', but the interpretation of this concept, as well as practical implementation, pose special difficulties. However altruistic the intention, a variety of political and administrative barriers arise in trying to move from the outright pursuit of economic growth towards ecologically and socially acceptable forms of development strategies. In particular, existing interests may be challenged and new programs involve substantial adjustment of extant provisions, threatening profitability, employment and power. In such circumstances strong countervailing forces for the status quo may emerge. The difficulty is exacerbated for federal nations in that various levels of government, as well as private corporation positions, may be challenged.