"Hedge fund manager turned environmentalist Tom Steyer is challenging fellow billionaires, Charles and Davide Koch, to a debate on the Keystone XL pipeline.

During an interview on HBO's 'Real Time with Bill Maher,' Steyer formally challenged the conservative Koch brothers — who made their fortunes in the fossil-fuel industry — to a debate on energy policy, specifically Keystone, subsidies for the oil industry, and climate change.

'Today I am issuing a formal invitation to Charles and David Koch to come out of the shadows and join me in exactly what they’ve requested: a free and open debate,' Steyer said Friday night."

Laura Barron-Lopez reports for The Hill April 26, 2014. [2]