Associated Press: A San Francisco billionaire -- a friend to Barack Obama and a major Democratic financier -- is embarking on a mission to block TransCanada's proposed Keystone XL pipeline by targeting voters who cast ballots for the president in last year's election.
In an open letter to Obama, written by Tom Steyer just two months after hosting the president at his home, the climate-change activist says his political action committee, NextGen Action, is launching a campaign to "intensify our efforts in communicating...