A new ad out this morning from John McCain's campaign features Barack Obama praising the Arizona Republican for his work on a a bill to reduce greenhouse gas emissions. "The right approach begins with the proposal put forward by Senator Lieberman and Senator McCain," Obama is shown saying. "The Lieberman-McCain bill establishes limits for greenhouse gas emissions. It's a framework that's not only good for the environment, it's also good for business. I want to thank Senator Lieberman, as well as Senator McCain, for the outstanding leadership that they've shown." The ad will air in key states. Watch it:
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