Greenwire: Billionaire environmental activist Tom Steyer stood on the steps outside City Hall here recently, surrounded by hundreds of people protesting for a $15-per-hour minimum wage.
Wearing a gray T-shirt with the "Fight for $15" slogan -- pulled over his customary business shirt and red plaid tie -- Steyer held a megaphone and chanted with the crowd, "I believe we can win. I believe we can win."
A San Francisco-area resident, Steyer, 58, became known in the political world for spending part of his...