The candidates differed somewhat over how best to address climate change

Inslee, who has made the fight against global warming the centerpiece of his candidacy, reiterated his call for heavy investment in green technologies as a way to create jobs while slashing carbon emissions.

“The biggest decision for the American public is, who’s going to make this the first priority?” Inslee said.

O’Rourke talked up his $5-trillion proposal to slash carbon emissions and Castro said he would issue an executive order for the U.S. to rejoin the Paris climate accord, which set international standards to fight climate change.

But Ryan voiced skepticism, saying that Democrats have lost the working-class voters “from forgotten communities” in the industrial Midwest by leaning too heavily toward environmentalism at the expense of economic growth. Without their support, he said, “none of this is going to get done.”