"The struggle to expand or restrict the nation's action on climate change in the next presidency intensifies today in Iowa.
In tonight's caucuses, Democrats are fighting in part for the title of the best climate candidate. All three presidential candidates propose strong action on clean energy as a sign of their commitment to advance President Obama's unmatched efforts to address climbing temperatures and to attract core voters.
Republicans promise the reverse. Most have pledged to roll back Obama's rules to cut carbon emissions by 32 percent in America's electricity sector. Some say the climate is changing. But the two leading Republicans say it's not because of people. A few say that humans contribute to warming; none argue that it requires a strong response."