Throughout Tuesday's Democratic National Convention speakers hammered at John McCain's energy policy in seeking to make clean energy a major issue in the presidential campaign.

Governors from Kansas, Wisconsin, Pennsylvania and Montana with good records on promoting alternative fuels and energy efficiency seized the national stage opportunity to make the oversimplified point that Barack Obama is green while John McCain is a friend of the oil industry. Keynote speaker and former Virginia governor Mark Warner was one of several speakers to plug Obama's plan to put one million plug-in hybrids on the road.

While McCain's environmental record is mixed (he did co-sponsor major legislation to combat climate change that his Republican colleagues defeated), he has recently embraced offshore drilling. That point was repeated time and again by Democrats. The line of the day went to Montana Governor Brian Schweitzer, who said that energy independence by drilling for more oil isn't possible even "If you drilled in all of John McCain's backyards -- even the one's he doesn't know he has." (Watch his speech here.)

The democrats also put Jerome Ringo, the president of the non-profit Apollo Alliance on stage, to tout the green collar jobs that Obama wants to create by investing in renewable energy, as well as clean tech venture capitalist Nancy Floyd.

It will be interesting to see if the planners of the Republican National Convention respond to all of the green talk with an elaborate showing of support for clean energy during their time in the spotlight.