Looking back over the past century, I was intrigued to see how the political attitude toward the environment has swung back and forth. We¿ve had periods when the voting public had an urgent sense that the government should do more to protect the natural world. I¿m thinking of Teddy Roosevelt setting aside vast areas of land for conservation, and Lyndon Johnson signing sweeping laws to fight pollution and protect wilderness. Then we¿ve had other times when people were more inclined to let the free market sort things out; Ronald Reagan vowing to get government off the backs of property owners, or Warren G. Harding rejecting a ban on interior paint containing lead. In 2008, as voters become more aware of the threat of global climate change, both candidates are calling for more assertive government action on energy and the environment. What do you think? Is this one of those watershed elections, when the pendulum swings back again?