Greenwire: U.S. Chamber of Commerce President and CEO Tom Donohue charged today that recent defections of high-profile companies from his group are part of an “orchestrated pressure campaign” by environmental groups and signaled that his influential business association won’t shift its stance on climate change policy. “We’re sorry to see them go,” Donohue said. “But it is sort of interesting that we have turnover all of the time and these four companies sort of woke up one morning and all …