LA Times: If you were going to pick a single issue whose treatment exemplifies the forces at work in this midterm election, the best choice would be one over which there’s been relatively little contention — climate change. That’s not because there is any broad agreement among the candidates on the severity of global warming or human activity’s contribution to it. To the contrary, the question seldom has been discussed in this campaign because views on it have become utterly politicized. Skepticism about…