WHY IT MATTERS: Issues at stake in election - Article Photos 25/40

FILE - In this March 16, 2011 file photo, exhaust rises from smokestacks in front of piles of coal at NRG Energy's W.A. Parish Electric Generating Station in Thompsons, Texas. Everyone wants clean air and water. But people also want to drive their cars whenever they wish and light up a room by flipping a switch. It’s a never-ending balancing act for government as it tries to protect health and the environment while promoting economic growth and jobs. (AP Photo/David J. Phillip, File)