Billionaire hedge fund manager turned climate activist Tom Steyer is marshalling resources to help democrats maintain the Senate during this year’s midterm elections, with climate change as a major electoral issue. He’s putting $100 million toward the cause, but some question whether that’s enough to counter the more than $400 million the Koch brothers’ empire will use to fund ads and a network of organizations.

“Opponents and even some Democrats also question whether Steyer will find broad support for a platform that consists of issues like climate change — traditionally, not a huge vote-getter at the polls — and opposition to the Keystone XL pipeline,” Andrew Restuccia and Byron Tau wrote in a Politico story today.

“It’s good to see people trying to compete with the Koch brothers and the other dark money outfits they’re running, but as somebody who is focusing closely on the Senate, I’m not sure what Mr. Steyer is trying to do is going to help keep the Senate in 2014,” Jim Manley, a Democratic strategist and former aide to Senate Majority Leader Harry Reid said. He added, “I don’t think that he alone can compete with the Koch brothers and their like-minded interest groups.” – Politico