"Businesses don't own the sky ... and if we want them to stop polluting it, we have to put a price on all pollution," Obama told voters in October. The first-term senator from Illinois is known as a team player, advancing a middle-of-the-road agenda with partners in the GOP. But in October he busted out a bold clean-energy platform that won praise from fellow Dems and green leaders.
Battle Cry: "Some of [my environmental] policies are difficult politically," he said recently. "But being president of the United States isn't about doing what's easy. It's about doing what's right."
Green Chops: He's played tough with Detroit, in May calling carmakers' current path "unacceptable and unsustainable." He partnered with Republican senators—and fellow Democratic candidate Joe Biden—to sponsor the Fuel Economy Reform Act of 2007, calling for a 4 percent annual increase in fuel-economy standards.
Power Points: Like most of the Democratic candidates, Obama backs cutting carbon emissions 80 percent by 2050, and he has an ambitious cap-and-trade program to get there. "It is going to require a thoughtful approach that accounts for the possibility that electricity prices will go up and low-income people [will need to be] compensated," he says. He vows to make us 50 percent more energy efficient by 2030 and require a quarter of U.S. electricity to come from renewable sources by 2025.
Outside Moment: "I have fond memories of visiting Yellowstone as a kid—marveling at the scenery, chasing after bison."
Eco-Hero: Rachel Carson.
Hmmm: In January, he cosponsored a bill that would fund the development of alternative fuels from coal—which thrilled mining interests in Illinois but incensed eco-activists. In June, Obama backtracked, refusing to support any similar plans unless they include adequate environmental safeguards.