What role does natural gas play in a ‘clean energy’ future? Separating spin from science in TV ads

"Clean energy" seems irresistible. Could you oppose energy that doesn’t pollute?

But the term’s imprecision leaves it open to interpretation — and sometimes manipulation.

Wind and solar are "clean," right? 

But is natural gas clean — or at least less dirty?

Natural Allies for a Clean Energy Future, a group backed by the natural gas industry, is trying to sway public opinion, particularly among Democrats. The group doesn’t call natural gas "clean energy," but casts it as a companion.

The pitch, backed by prominent Democrats such as former Sen. Mary Landrieu...