Should the United States government require citizens and private industry to further "green up" or else?

The USA is already the greenest nation on earth. Do you know that the air coming into California from the Pacific is why the state can never meet the EPA clean air standards. The air leaving the US for Europe is cleaner than that leaving Europe for Asia. So the US is already walking the walk and per capita is the lowest polluting nation on the face oft the earth. It should be when is the rest of the world going to catch up. If we could replace every coal fired power plant with nuclear plants we would be below even the strictest air quality standards. You can thank your local environmentalist green freaks and their energy company funded pogrom against nuclear power for the small amount of pollution we still have.