At the American "Live Earth" concert:
"However, Etheridge aside, it was nonmusicians at this concert who made the most passionate pleas about demanding action for the environment. "Get rid of all these rotten politicians that we have in Washington, who are nothing more than corporate toadies," said Robert F. Kennedy Jr., the environmentalist author, president of Waterkeeper Alliance and Robert F. Kennedy's son, who grew hoarse from shouting. "This is treason. And we need to start treating them as traitors."
Source
They clearly don't rely on reason to promote their beliefs. The shakier the evidence gets, the hoarser they get.
