But the Lieberman-Warner bill isn't the only "cap-and-trade" proposal floating around on Capitol Hill these days, so why is it making waves?

FORBES: Magazine Article

In 2008 another piece of major legislation was introduced: the Lieberman-Warner bill, which would implement a nationwide cap-and-trade program on carbon emissions.

FORBES: Magazine Article

Then there are these current Democratic governors: Iowa's Tom Vilsack, Virginia's Mark Warner and New Mexico's Bill Richardson.

CNN: The veepstakes